Lots of post's and opinions on this subject and the Wiegand mount (drill n tap) usually comes out the winner.
One question that you have to ask yourself is if you really want a couple of holes in the top strap of that fine bisley?...I did have this work done as most of the post's right here at GBO told of poor results with a detachable type.
My Red Dot is the Bushnell Trophy Red/Green model and I have no complaints. If you wanted to step up one, the Red Dot Ultra dot gets very good reviews. If you have the cash, a holo type like a burris fast fire is great just for the ability to see through and around that sight.
If you do decide to go with a dot, holo, or glass, The very affordable if not somewhat ugly Hogue monogrip is an excellent platform to launch a bullet from. I can post before\after pictures if you wish.