G'Day Deno,
I admire the idea and your courage -financially- but wouldn't it be a whole lot cheaper to simply buy an aircraft already fitted with the floats / wheels?
I seem to recall a beaver in Derby in 'those good ole days' being valued at around the $90K mark, (then) and a set of the floats / wheels thingies being about the same.....EXTRA!
Wasn't / isn't there, a Maule or something already equipped and available that could do the same for you?
Already certified - and a going concern would seem to be more appealing...?
Best Regards,