If it's been bored sighted properly (that's a sketchy subject, the pimple faced kid at Walmart or BPS seldom knows their butts from a hole in the ground) then I'd start at 25yds, put it dead on. Then you're ready for 100yds. I prefer my leverguns and non-mag bolts be 2" high at 100yds so that most are essentially dead on at 200-250yds depending on caliber and load. For my faster guns (7mag, 300Wby, Lazzeroni Warbird) I'll have them 2.5"-3" high at 100yds for 300-400yd essentially dead on holds. www.jmballistics.com is a great tool for printing out essentially any commercial as well as handloaded hunting round and the choices for ranges and conditions are limitless. Now DON'T make the mistake of thinking "Well this says if I put my bullet xyz at 100yds then I can simply aim as it says all the way out to a quintillion yards." That's NOT the way it works, you GOTTA shoot your gun to make sure it's hitting where you are aiming. The calculations are simply mathematical and "best case scenarios". When dealing with guns and the outdoors you are tied to "REAL case scenarios"...

Likewise, all of this is dependent upon how high your scope is from the centerline of bore in your rifle! I prefer a 1-1.5" line of sight above the line of bore. (When you are looking at printed ballistics tables, the industry standard is figured at 1.5" sightline to boreline) If you have exceptionally high rings or especially if you have say, see-thru mounts, then you'll have to shoot and see where everything ends up because the numbers obviously change as the line of sight to line of bore distance increases! (That's another reason I like the jbm sight, you can put the sightline-boreline figure of your gun into it's factors to get a reasonable "expectation/baseline" of what you should be able to expect on the range.)

Rest wise, obviously a stable table and rest is best. But you DONT have to have all that if you just can't manage that. LOL my best "rest" and comfortable shooting "platform" is the perfectly flat hood of my farm truck, a 1980 Chevy 4x4. It's just the right height to stand beside and shoot off of. Sandbags, commercial rests, rolled up carpet, whatever you want to shoot from works perfect on the hood of "ol blue". (Just make sure when shooting from/off a vehicles hood or roof that you DONT have the windows less than 90 degrees from the muzzle of your gun or you could crack glass, ESPECIALLY if there's already some cracks/holes in the glass to begin with! A rifles crack/muzzleblast will play hell on existing cracks and stars in glass!) If you have a muzzlebrake/boss on your rifle than be sure and increase that 90degs to 180degs!!! I have a 500yd range on my farm and many a "competition" has been had from the hood of "ol blue" at over a 1/4 mile!