New to putting aftermarket grips on any of my S&W revolvers, I tend to leave things stock on any brand 6 or 7 shot, in this particular case a 5 shot. But I made an exception after firing a S&W .460 with Nills wood grips at my local range. Loved em! They were a bit big

SW18X8XL

So I went with the regular sized ones for my S&W .500 mag.

SW18X8

My question is my title, how tight do I tighten these wood grips screws?

They were a bit tough to get on, had to use a rubber mallet to seat the dowel peg and get the grips together close enough to begin tightening them with the screws. I'm just afraid to split the wood going too tight. Would it be best to just tighten as much as I dare and then take it out shooting and go from there or should I just torque on them now and get em as tight as I physically can by hand?

Last pic of the back of grip near the top seems to still show a crack between the two grips sides and a tiny difference in height, enough to barely feel the difference when I run my finger across grip sides there. Is some fractional differences normal on aftermarket wood grips?

Appreciate any advice.