Go with the box fuse!
To me the reason you would build a profile is because a flat fuse is ez'er and simpler to build but it seems that as you get bigger it get more complex to build. I still think a box fuse is the simplest and quickest to build if it is a kit! Profiles were popular kits but they were only just a box of sticks! I think you could design a much better plane like your hard bet if you drop the profile fuse.
just my 2 cents!

Rickc2009