GeoF, One nice thing about the slower hardner, it gives you time to have your panic attack and still recover enough to still do the right thing.  ;D

Work on a small cut or area. Build some confidence in what you're working with and the time it takes. Keep your batches of mix small. Give it time to cure. No rush.

If you think your job is making you nervous. One of may first experiences was I cut a hole in the bottom of a brand new never been wet racing canoe to install a Andersen Bailer. Talk about measure twice.

Don't even think that one of those bailers will work in tripping canoes. Hydrostatic pressure is exponential. Even a heavy slower race team can keep it from working right, let alone a tripping canoe full of gear.