I'd be more likely to go with longer arrows if the bow isn't particularly efficient with lighter arrows, or if I didn't want maximum speed.
If you want light arrows, I'd try to make it so the arrow/field point sticks out of the back by just an inch (more for a broadhead..)
I tend to use 32" arrows (nock groove to base of field point) with 26-28" draw, and also 32" draw. For the latter, I release when I feel the head to avoid overdrawing. Though it's tricky to do consistently..
There's some contradicting evidence that longer arrows are more spine forgiving. Seems legit in my experience