OL,
All good stuff but I think you'll find that after every solo trip you'll evaluate things and look for keeping items that serve a dual purpose.
One example. You have a knife, you can make FUZZ sticks and light that with BIC or Firestarter stick. That eliminates taking that pencil sharpener/cotton balls.
You mentioned a wire saw. I've used more than a few models, even so-called military grade. Poor performance at best.
I'd buy a small folding saw that is big enough to use to clear limbs on portage trail if need be. You can cut even wet firewood and use a decent size knife to BATON (split) your wet wood to get to the dry interior which you then make Fuzz sticks from.
I have both of these. The Mora knife is my new paddling knife, I like the Orange color for paddling, hard to lose. I have the saw too but don't bring it on canoe trips. I bought both separate, This is a real deal for both together. The steel in Mora knives is EXCEPTIONAL for the price.
(You need to Login or Register to view media files and links) I have a large Japanese style pruning saw that is strapped to outside of my Ditch Pack. That's why I like to carry it first trip across the portage.
I have a small daypack that sits in front of me in the canoe it's clipped by a carabiner to paracord loop between portage pads on the yoke.
If the conditions are right, I like to take the heaviest pack across first with the Ditch Pack clipped by carabiner to the D ring on my weak side which for me is the left side. I cradle the Ditch pack with my left arm against my body. My right hand is free to carry my Double paddle as a walking stick.
Not everyone uses a double paddle, but the advantage for me in securing your Ditch pack like this is your NOT trying to look over a front portage pack that's clipped across your chest.
I've found that it's very important to see where your stepping on portages. Having an unrestricted view has saved me from falling many times. Other's will feel different.
If I 3x portage it's the Ditch Pack and the canoe.
I would say your best bet is to set your pack up the way you listed, look to eliminate items if practical and then see how much it weighs and determine if you're okay with that?
Every trip is a learning experience, I doubt many people keep the same set-up year after year without some adding/subtracting of gear.