Would a 340 cut to 29" with 200 grains or so up front be good out of a 60# grizzly? My draw is 27.5 or so

I think it would be on the stiff side.

You think making them 30" would be better

I never just cut a carbon without shooting them full length first.There are plenty of used carbons for sale that were cut first and then found to be too stiff.

It would be much easier to mount the weight you want to shoot on a shaft and trim back as you tune to get it just right.Arrow length has a huge effect on what works and is the most fool proof way to tune carbons.

I have a bow that is 10# up from yours that I use 340,s cut to 29 but have 250 or more up frount, I pull 28".

JRY309, VERY GOOD POINT