Watch the EGT rise. If it peaks and then starts to fall again while on WOT then the chances are that you're starting to detonate. This is due to the detonation causing the combustion chamber temp to rise, but the exhaust gas temp to drop.....dangerous and will result in damage.

If you're up to 1250 degrees then you're pretty close to ideal, but if you intend to do lots of flat out riding then I'd be tempted to throw some bigger brass in there to drop the temp 50 degrees. This might knock off half a pony, but it'll keep that half a pony less for longer.

Messing with the ignition timing can change your EGT. More retard will heat up the combustion chamber later, so less heat is lost to the cooling system and more heat escapes into the pipe, so EGT will rise. More advance does the opposite, with more heat being lost to the cooling system before it exits the exhaust port, so EGT will drop.