Merc props @ full retail are a similar price but there's a lot more choice, specially in 2nd hand. What's your top speed? I've got a 19" 4 blade which would suit a wot speed of 45 ish knots at a guess. It would be similar to a 21" 3 blade.
I'm guessing that the profile of yours is such that your 26" dia is giving a similar pitch comparison to the merc props, ie in terms of merc 14.75" 3 blades, a 23" would be close if not slightly big for your boat. Although I'm not considering the likely reduced max rpm range of your 4 stroke.
The one thing I found when experimenting was the lower fuel consumption of a small pitch. Obviously you need to make sure you don't exceed max rpm (but that's what rev limiters are for) and you'll probably see your top speed drop a knot or two. But you don't fly around at WOT so it's not really an issue