What kind of speed can I expect to lose if I drop the weight down to 65 or even 60 lbs? Right now at 70 lbs I'm at 273fps with a 27.5" draw, 65% let off, 400 grain Gold Tip 5575XT and shooting an 03 Razortec. I know speed isn't everything, but this is the first bow I've owned that put out decent speed and don't want to drop too low.