yeah by all means try the needle but that wont have any effect at wide open throttle, chances are it'll be fine with the 240 but just for peace of mind you could stick in a 250, when all said and done without specialist measuring equipment it's all trial and error
Theres no way you'll need to move the needle 2 notches I think it would run rough if you do...maybe 1 maybe none you'll just have to try it
Cant see youll need 260 MJ either just too big a jump...but again, theyre cheap enough so if you want to try 260 and 250 and compare?