Bought a dimpling jig, which says to use a 5/32 bit, but a a 11/64 doesn't have as much side play. Already bought a bit, should I return it and get the 11/64?
This is a FSB clamp on, so I need it to be as straight as possible.
And, this is a pencil barrel, so should I go the depth of the drill bit tip, or less that that?

Clamp-ons don't require a dimple.

This^

Dimples are only a good idea for set screw type. Return everything else.

So if the sight is hit at some point, it won't twist off center?

What would be the point in making a dimple if there is no set screw to fill said dimple?

Ok.. was looking at two different builds I am working on..

They can and have rotated even when tight and impacted. If you bought a dimple jig for a clamp on style FSB, you just wasted $$$.

5/32 is the bit size to use when using the SLR Rifleworks jig, 11/64 is the spec for the BRD jigs. Neither of which will be useful for a taper pin or clamp on style A2 FSB. BRD does make a big for drilling A2 FSB's, but doesn't not sound like the jig you bought. Use whichever bit size the manufacturer of the jig called for.