I have a few ? on scopes im looking for a little help picking one

[bigrich954rr]

I need a scope for my 50cal rifle. I want to also use it on my other long range rifle. Because i dont want to spend this much money and just use it once a month. What is illuminated Reticle? How long does the battery last? Does it really help seeing the crosshairs? Looking at Leupold Mark 4 8.5-25xx50mm LR/T illuminated Reticle and IOR Valdada 9-36x56 Tactical Scope: 35mm.
Is there any down falls to the 35mm tube?
Looking for any opinions on these brands or your experiences with other brands. i will be shooting out to a mile on the 50cal whats the lowest max power you think i could get away with and still see good out there. On my long range rifle i only hunt out to 900 yards so i know i dont need 36x power

[MachV]

Most if not all of my longrange shooting is done at prairie dogs in good light so the illuminated reticle never got used(had a NF 8-32 and 12-42)For callin coyotes at night the Bushnell Firefly works ok,for short range.
Traded the NF 8-32 for a 35mm 6-24IOR/non illuminated and got the good end of that trade!The problem so far has ben overtightening the rings and tourquing the power adjusrter so bad it would not adjust(the IORs are kinda fussy about that!)Getting the right hieght 30mm scope rings can be challangeing but try to find 35mm?
I had a 16x IOR on my 50BMG and with the help of the MP-8 reticle I could zero at 100 yards and still get out past 2000meters but 16x is only good for prairedogs to 1500 or less.
Now The 30mm 6-24 IOR sits on the 8twist 22-250,the 35mm sits on the 6-284,one 16x is on the 6.5-284 and the other is on the 204?
For deer size targets a 16x scope is enough and most of the time all the mirage will allow you to use.