I've been flying my Katana for several months and have not had a shear webb problem yet ,but I will besure to check mine tonight my saving grace maybe the bolt on wings two of us built the GSP katana at the same time and we came up with several mods, one being bolt wings using studs and wing nut on the inside and we installed a top hatch and sealed the bottom hatch. some reinfocement was add to the engine box as well as some added to the counter balance s on the elevators , I have cracked both of them .
mine is over powered if that's possible ,brison 2.4 swinging a zinger pro 20X8 prop. Even with the engine and ignition battery still had to add 1.5 oz of lead to the nose to balance in the rear of the CG range.
total weight is 12lb 10oz ,a buddy is finishing one now and he is under 12lbs with brison 2.4.
I have really pushed this plane to the limit and the only thing I dislike is at high speed and full up elevator (60 degree's) it will tip stall and drop the right wing ,this is also why I have cracked the elevator counter balances. this is a great flying plane .I like it so much I'm thinking of buying another just to have it in my personal stock ,you know for the one time I take off and hit a light pole or something.

WYLDMAN