To answer your other question. 10 x42 for example. The first # tells you the magnification and the second # tells you the diameter in mm of the Objective lense I believe. The bigger the lense in mm the more light transmission is a basic rule of thumb. But also it depends on the lense itself. Like I said before you need to compare side by side. Just like everyhting else, there are different levels of qaulity within the same brand. The more dollars the better construction and lense. Not all 42mm lenses are equal even in the same brand (Nikon, Bushnell or Swarovski).
Also I got that pair cause of the 100% gaurantee to be fog proof. There is nothing worse than try to scope out a big buck in late November or December in sub zero temps and having your lense fog up . Just another thing to keep in mind
So I guess given the information you gave above, I think the experts would say that a 8×42 would suit you best. That is what all the magazines I read say is the best. I guess I disagreed with that and like the little extra power and got a 10×42.
I like the extra magnification the 10 power gave me and the 42mm diameter in the lense is big enough that plenty of light was captured with the Monarch ATB. The other Nikons I looked at in the same 10×42 size were cheaper but when compared side by side the Monarchs were way clearer and had better light transmission, something that I wanted/My preference so I paid the extra cash. I think the others had a different lense ssytem. I know a lot of people (myslef included)get the 25 mm size binocs and those are handy light and compact, but you will loose low light condition performance. That is the time the big boys usually pop out or hangon the tree line. That is when you need the binocs the most. The Nikon Pair I suggested above is still pretty slim and non bulky. I also higly reccomend getting that Bino system strap. These thingsa are awesome and well worth the $20. It makes it so you do not even know you have binocs on and can wear them all day with no neck fatigue!
Good Luck, get to a store and compare. I would think you could find a more than adequate pair to fit your needs for around $300 or less.