How do you index wood screws ?

[Tom]

Hi
I'm installing the trigger guard on my new home made stock, I say that because I'm dealing with a new installation and new holes.
My problem is if I tighten the screw and when tight it lands a half a degree past a perfect line up I'm looking at another half turn.
Needless to say this just happened. I started to take a little off the back of the head and due to the coarse thread of a wood screw it will sink in quite a bit for a half a turn, as opposed to a machine screw.
I shaved off as much as I dared and the best I could get is a quarter turn and the head now sits lower than it should.
As a last resort I welded up the head and cut a new slot in the correct orientation. It's done but far from perfect, it's hard to weld the very edges of the old slot without melting the whole head off.
There must be an easier way but I can't figure it out.
I have no interest in using washers so that's out.
Any advice greatly appreciated.
Thanks, Tom