Is cut down on the gear weight/Quantity. Do everything you can to dissipate that.
As a avid soloist and lightweight hiker, My gear weight is 47.265 lbs (I am 158) & my dogs gear weight is 21.876 lbs (She is 162).
Sounds strange to some, but-
"ounces = pounds over distance".
The same is true for dimension-
"size = mass over area"
Get rid of anything that is equal to surface area. ie: wrappers off canned goods (identify with a sharpie), take items that are in a cardboard box out & put into zip-lock bags (unless already bagged in the box, then just discard the box). Get rid of "redundant equipment". Carry "multi-use" items. Only take the maximum cookery (do you really need three different pans and 5 different pots? Learn the "one/two dish cooking method). Etc. Etc...
This should open a DRASTIC amount of room in an existing canoe & save $$$$.$$ in the long run.
Just for alittle example, I use a 9ft kayak if I am by myself. I also use a 16ft canoe if it is me and the dogs (162lb English Mastiff & 48lb English Bulldog). And no boat at all if it is just me & the Mastiff hiking. So you see, my two dogs = you... I = your brother & the gear = about 1/2 yours, all in a similar boat. LOL