Just a thought....
Before you start putting bigger rotors on (naturally, a good idea) has anyone considered using a better caliper? As I am not a ace owner, I am not able to see the clearance between spokes and rotor, but I was thinking something like a pre radial GSXR tokico or perhaps CBR nissin 4 pot caliper, both very cheap and abundant on ebay. May need to upgrade the M/C also.
this is a popular upgrade to the SV650 which come with flimsy 2 piston calipers (which are probably better than the stock ace ones).
Also I had the thought...
the front rotor of the ace has quite a bit of offset, if you got a larger rotor with zero offset, an adapter could be made to correct the bolt pattern and be the thickness of the offset to give correct disc spacing? Once again choose something that's around 280mm and easy and cheap to get.