One of the techniques I learned (here, probably) that "cleans" the wells up nicely is that if you slightly undercut your wells with the gun, even if your gun handling or template is not quite up to snuff, you can then sand the wells clean with a paint can cap and some 220 grit sandpaper wrapped around it. Not only does it sand things round and smooth but it also can sand the base of the well with some sandpaper glued to the base of the cap (use the self adhesive paper for this).

But it is certainly an acquired art. I'm still working on getting them just peachy!

David.