Most 1" tactical scopes will have 60+MOA of adjustment - that will get you to 1200y+ with 100 yard zero. No doubt 30mm will have more room for adjustment - but I don't think it's some kind of arbitrary must have.
There are so many qualitative variables to be considered (glass, knobs, clicks, construction, zoom, etc) - that the quantitative concerns should be last (tube size, objective size, length etc).
I would respectfully disagree with you on this.
First off, just beacuse a scope has some specific amount of total adjustment (60+ moa in your post) doesn't mean it has that much USABLE adjustment. I used to run the 1000 yard matches at Red Castle and many times people would show up with their rig and try to shoot 1000 yards, only to find out that their scope lacks sufficient adjustment to get them there.
For argument's sake lets say you have a scope with 60 moa of adjustment and your 100 yard zero is in the exact optical center of the scope (most are not), giving you 30 moa of usable + elevation and 30 moa of useless - adjustment downwards. With a flat base this is about normal because the optical center of the scope gives the best picture. If you change to a 20 moa base to shoot longer range this puts your 100 yard zero well off the optical center but leaves you approx. 10 moa above optical center at 1000 yards, a reasonable compromise.
Now, lets say you are shooting a 308 rig utilizing the 175 Matchking bullet at about 2700 fps. This takes around 35-36 moa to get to 1000 yards. With a flat base you are out of adjustment somewhere around 800-900 yards. Even with a 20 moa base you can be right at the top of the adjustment range due to variances in how bases fit onto actions. I have a remington action that is so out of true with the bore that I have to put 5 or 6 moa of additional elevation and some windage to get it centered at 100 yards. An additional issue is that adjustments become inconsistent as you are closer to the limits. Close to the center of adjustment, you can get a nice even 1/4 moa per click but towards the limits you can have no actual change of impact even though there are clicks left. Seen that several times when people are doing a box test at 100 yards.
There is good reason that 30mm and bigger scope are becoming popular. A huge reason, particularly for longer range, is the amount of light and clarity that the larger body allows to pass thru. I have discussed it at length with a couple of manufacturer rep's who participate in tactical matches during down time but still don't have a good feel for what goes on inside of the scope. Ther is a lot of very precise stuff in there to make everything work correctly. People who only shoot out to 300 yards often think that 1" scopes are perfectly acceptable right until I have them lay down and compare their stuff up against good quality optics.
Cheap 30mm scopes often utilize 1" internals so that a manufacturer can charge a premium without actually having to design something from scratch so you have to be careful what you buy. One big red flag is if a 30mm scope has the same total adjustment amount as a 1" model.
Bottom line, if you figure on shooting out to 1000 yards or past you actually do need a 30mm scope body with enough elevation adjustment to get a VERIFIED couple of hundred yards past the maximum yardage you anticipate.