ORIGINAL: blw
Enlarging the ailerons on the tips could promote flutter since they are strip ailerons. The Sig Kavalier has that problem at high speeds. Also, the tips is where you will be vulnerable to either tip stall problems, or vortices for sure. The best bet is to narrow them at the tips and widen them towards the wing roots. The flutter possibility is remote, but vortices interferring with aileron control isn't.
When I widened the ailerons on my latest 4* 40, I rounded the tips and there has been no problems with fluttering or tip stalling. The clipped wing also gives a much better roll rate with not much affect on the landing speed.