I paddle a tandem solo with a double paddle as my primary paddle.
I'm using a rental SR16 so lowering the seat isn't an option. If I could I'd lower the seat a few inches.
Trimming your load is paramount solo. I push my heaviest pack forward and the other crossways, keeping both below the gunnels.
If I could I'd take out the stern seat to allow more weight in the bow. For now I use a dry bag filled with water for ballast if it becomes necessary.

No way your tandem will perform speed wise with a dedicated solo,( a double paddle helps here) but there are positive tradeoffs.
Much more stability, easier to load gear in and out of. In shallow water the extra hull volume means you can go shallower than a narrow solo. Depending on water levels that may be a big plus.

IF I owned a tandem, I'd pull the stern seat out when solo to save weight.
I'm sure you could heel it over from a sitting position with a little caution. With the lowered seat, I think it would be just a matter of learning it's limits. You also want to turn the yoke around so you don't have to turn the canoe around on landing.

Another point about trimming your load properly. True solo or not, your better off a tad bow heavy than light, especially if the wind picks up. That extra foot in the 17 makes it even more important you get it trimmed right before you head out into the open water.

I've got a Bell Northwind.  Haven't yet purchased a solo canoe and like you only have room in the garage for 1 canoe.  Last couple years, I've used the Northwind on my solos with a yak paddle as mentioned by ST.  I removed the bow seat and replaced it with another thwart.  Also moved the stern seat forward a couple feet.  No problem with canoe structure as far as I can tell.  Last summer was my 17-day solo.  Can easily make 12-15 miles in a day double portaging unless the wind is blowing hard against.

I know a true solo canoe would make solo trips much easier.   Hope to get one this year or next.

I solo in a 17'6" tandem, and am quite happy with it. I don't know if I would try heeling the thing fully loaded from a sitting position, but overall I find the handling issues to be minimal. Plus it's nice to have lots of room to put your stuff.

Of course it depends a lot on the canoe design, but I've only needed to worry about fine-tuning the trim when the canoe is empty: the bow can get blown around if you're the only weight in the canoe. But then I also have the option of kneeling further amidships if I need to move the canoe's centre of gravity forward. Of course trim is usually only a problem with a head or crosswind; with a tailwind you want the weight to be further back.

The only time I've found manoeuvreability to be a problem is when it's windy and I'm on a narrow twisty stream. You are heading around a corner with the canoe lined up perfectly, then a big gust of wind comes up and throws the bow out of line before you have a chance to react. At least twisty stream banks are usually soft.

You're not going to be as fast as either a solo canoe or a tandem, but the daily mileage hit compared to a tandem depends a lot on who your normal paddling partner is. For me, the difference is quite small (better not let my wife see this!), and depending on your fitness level, 12-15 miles per day should not be too difficult. You might be able to do 20 miles if you push it or have a bit of a breeze helping, and not too much portaging. (btw I use a regular wooden single blade bent-shaft paddle).

I usually triple portage, at least on longer trips. Rather than try to load up too much and risk injury on an unexpected slippery section, I prefer to take a light load on the first trip, scout out the portage if I'm unfamiliar with it, take some pictures, and clear out any low-hanging branches. Then take the canoe on the next trip, and the heavy pack on the last trip. I like portaging!

I've never tried reversing the yoke, but maybe I put in in backwards to begin with. I only have a single thwart (the yoke), so I like to put my head in the "bigger" space rather than the "smaller" one. Maybe the decision depends on the canoe design, maybe I just have a big head !

I've never tried lowering the seat either. I prefer to paddle sitting with my feet tucked under the seat part of the time, so I need enough room to fit those size 12's. With a lowered seat, you won't have that option, so you might end up in a situation where your legs are stretched out in front of you for the whole day, and your only recourse is to pull your knees up to the point where they interfere with your paddling stroke.

Remember too, that if you move the seat and then you want to go on a tandem trip, you will either have to move it back or your bow paddler will be stuck with your new seat height.

So I would recommend you buy the tandem and take it out solo without modifications. Then after a couple of trips, if you need to, you can think about moving stuff.

Hey thinblueline,

You can also just rent a solo if you don't have room to store one.  Sounds like it would be a somewhat rare occasion where you'd really need it anyway.

As far as fishing from a tandem as a solo paddler because your partner doesn't want to go out, it certainly can be done.  As db noted, having some ballast up front helps a lot and your safest option is the bag of water.  I've used my 5-gallon collapsible water jug from camp for that purpose pretty successfully.  I used to use rocks until someone from this site pointed out the obvious flaw in that plan.  Doh!!

Yeah, Azalea, you have a good point.  There's no question that most* paddlers find a true solo canoe is vastly superior to a tandem paddled backwards from the bow and those are just a couple of reasons.  If paddling a tandem solo was all that appealing, the solo canoe niche would not exist, or certainly not to the extent that it does.

*some on this board are perfectly happy to paddle a tandem solo and think nothing of it, and this comment is in no way meant to disparage that point of view.  If they are happy, I'm happy for 'em!