Superdown: Sounds like a nice package you're going to pick up. The rear sight blade should come with a white outline, which may help you but honestly I always fail to really notice the white outline because when I focus on the target and square the front sight blade in the rear sight notch I simply don't pick up the white outline. I will, if I move my focus to the rear sight but once I have the sights square and on target, I'm 'fixed' until I fire.
Your 629 is stainless and the stainless front ramp should help in low light conditions and that little plastic wedge might not hurt, either. I think what you may find helpful in your quest is to have the gun in hand and see what your sight pictures look like in those early and late conditions. I'm sure you have dealth with these conditions before and it's tricky sometimes.
A very inexpensive and quick assist might be to add some (removable, of course) white or yellow florescent paint to the front sight to see if you can pick it up or square it in the rear sight any easier. I have used this on 3 of my carry guns fun years and it certainly helps pick up that front sight, both with the florescent effect and the lighter color (mine are blue).
Failing any or all of that and (most assuredly) the better advice from others, check our sponsors list to see if any catalog or specialize in what you might be thinking of. HTH and GL. Mikey.