Med or Large depending on the maker.
weaver refers to the type of scope mounts the scope uses. a weaver scope can mount on any rail size.
Check the scope mount makers web sites or call Remington.
The industry standard for scope mounts is the 6-48 screw. This is an oddball size due to the fact that it is only used for that application. Brownells is one source for such screws and related tooling. Larger magnum builders have opted for the 8-40 size, however, to stand up better to the rigors of the magnum recoil.
Magnification, Distance, Objective size, etc..
depends on the rifle and the scope. Most scopes will use 1 inch rings for that type rifle.
Your Winchester model 25 rifle will take any size scope that you see fit to use as long as the rifle is drilled and tapped for scope use.If your rifle comes with a 3/8in.milled receiver rail then you must use that size scope ring bases.I recommend that a good 4X power scope is all that is needed for the effective range of .22cal rimfire ammo.
Impossible to answer without knowing what your end state is. Even then, "best" depends on your pocket book, skills, rifle, etc..
50mm at least.I have found that with a 50mm objective you will need a minimum of high scope rings.Most medium hight scope rings will not give you the clearance needed for a 50mm scope objective.
Its a 20mm weaver rail. So almost ALL scope mounts will fit on it
While anything is possible,why would you want to use a scope of that power and objective size on a .22 cal.rifle?If your receiver has a built in 3/8in receiver rail then you may be hard pressed to find rings of the significant height to mount a scope of that size.I would recommend that you get a scope of 4X power.That is all that is needed for the maximum affect range of a .22cal rifle.
For that one, contact the Browning service department in Arnold, MO.
The numbers represent the power of magnification and the size of the objective (front) lens in milimeters. 6-24 means the scope has a variable pawer adjustable from 6 to 24 times magnification. The size of the lens determines how much light the scope gathers and the field of view.