metal overhang

I installed a metal roof on an old garage which is not straight or square, my question is, I have 1-1/2" overhang on on both ends of the fascia board but there is a bad bow in the middle of the soffit so I ended up with about 2-1/2" overhang in the middle, is that too much overhang for a 4" gutter, I don't want the water to run past the gutter.thanks for the help

I would go with a 5" gutter here. That is a more standard size and will give you a bit more room in the middle to catch the variance.

What is the recommend overhang range?

On standing seam, its less a function of recommended overhang vs. what is necessary to hemming to the drip/eave starter strip. The eave metal is what typically handles the capillary break and is terminated into the eaves trough.