Glassing Distances Help??

[FullCurlHunter]

I am scouting an area in CO using Google Earth. I have found a ridge that overlooks a huge valley and can see numerous high basins that are 3 to 4 miles away.
Will I be able to see Deer from this vantage point with:

A. 10x42 binoculars
B. 15x50 binoculars
C. 20 power spotting scope
D. 60 power spotting scope

I am just trying to get a feel for how close my scouting vantage point needs to be to find game with my binoculars and then focusing further with my spotter. Or if I need to get a lot closer than 3 to 4 miles away.

Thanks

 

[Toomanytracks]

Glassing deer at long distances requires good optic. Great glass doesn't make up for knowledge or the lack of knowledge. Buy the best glass that you can afford, know it's limits and glass within those limits. Mature mule deer can be one of the most difficult animals to find glassing. I have spent hours looking for thoses buggers knowing there in my field of view. A change of angle can make all of the difference in the world.

10x binos is a good start for an allround optic
20x40 spotter. 40 plus gets to be a strain on the eyes. ???

Here's a an 09 mulie hunt. Leica 77 spotter khales 10x42 binos
spotted a heave horned buck at 2000+ yds with binos made a mental note of the location continued to glass. Nothing better poped up We walked closer to where we thought he might be. We talked to the hunter glassing and asked if he saw what we had seen. He said it wasn't what he was looking for from his glass(10x). I break out the spotter and find him in 10 min of glassing feeding inthe timber. At 1009 yds were looking discussing his age score and possible stock. An hour later we make a go at him. At 100 yds he's still in his bed to my suppries he's in velvet. I have seen deer, great deer and trophy deer but this is one of those moments where your heart is in your throat. He's just a deer mid 50s full velvet and we just spent a half a day on the stock. Everything went like planed excepted we missed on judging mass. You can have the best of everything and still come home empty.

 

[Long Time Long Ranger]

It is not uncommon for me to stalk animals spotted from 2-3 miles away with 10 power Zeis binos. Or from 5+ miles with a good spotter.

 

[FullCurlHunter]

What is a good distance to use 10x binoculars for preliminary glassing and then be able to really scope them out once found?

Is it preferable to hunt/glass from across a canyon or get up on the mountain ridge above them and glass down potentially being seen/smelled?

Here is a picture of what I am talking about... The basin on the right is 3 miles away and the basin all the way on the left is 4 miles away. Would I be better off coming up the other side of the mountain and glassing down in?