David,
Some hunters do indeed use a spotting scope for a detailed search, especially at longer distances. But searching for long periods is much more comfortable with binoculars than a scope, because your eyes are much more relaxed when both can remain open and looking. (I do sometimes use a scope for long-distance searching, but leave a piece of tape on the scope, which I place across the left lens of my glasses when glassing for long periods. This allows me to leave both eyes open, rather than squinting with my left eye, but it's still not as comfortable as using a binocular.)
Normally, if I find deer with at least a 10x binocular, and if I can't tell exactly how big it is, or the deer I find is a doe and a buck might be nearby but semi-hidden, I then use the spotter. (It would be nice to always hunt country where it's always immediately apparent exactly how big a buck is in 8x binoculars, or where big bucks always are out in the open where both antlers are totally visible, but for some reason that doesn't always happen to me.)
There are many areas where your "stalk" hunting works very well for mule deer, but in more open areas it's not as effective. This is why my 8-12x Leica Duovid is my favorite all-around big country binocular. It might seem a little heavy to people used to light 6x to 8x binoculars, but evidently I long ago became immune to those thoughts, because I've found a slightly "too heavy" binocular far more effective than a too light binocular.
But it's also why I suggested in two of my previous posts that you bring both a smaller binocular and a big one on your hunt. One or the other will probably be more useful in whatever country you're hunting. If you can only afford one really good glass, I'd suggest you make it the more powerful one, and bring one of the smaller binoculars you already own for the other--probably the one you already prefer for your stalk hunting.
