So Burris XTR Signature are not the only solution nor even the best solution to scoping a precision rifle. However, they can do some things that will save your bacon or your hard earned money in certain situations. And if your facing one of those as noted above, use these rings with confidence....They just work.
So while I agree they might be helpful in some situations where a base isn't going to work or isn't available; going down that road as the first step does not make a lot of sense. Understanding what your intended uses are for your system and getting the best for that purpose within your budget, or deciding to save are better process.
Now, I'll make some rather large assumptions because the whole path of the OP is totally typical sounding.
1. He bought the Lowest cost 25x range scope because it looked to have the "field style features" (reticle and exposed turrets) and the power he would "need".
2. He has a Creed
3. He is on SH
4. He is concerned about elevation.
So my assumption is that he is hoping to shoot long range distances or even you might find in your typical PRS match (some over 1K). I will say that if the op never is going past 500m, then that scope and combo should be fine and my assumptions are wrong..
Now, he already has an investment that isn't best suited for those tasks.. Does he cut bait and sell with a hard restart, just spend another $40 on a 20 MOA base or go with the much more expensive plastic inserts? He already knows he can only use 20MOA.. The how idea of switching out insert to go to a mile, is just so.. IDK no words here, except except making pigs sing...
Again the main mistake, probably started with thinking that he needs 25ish magnification for longer range. But he would have been far better off with a used 3-15 that provides more travel (maybe with a couple extra $ even FFP) if he is indeed interested in precision long range.. Heck most the guys I know, even guys winning PRS matches run around 15x even on long range targets. I acknowledge that in this example it is about target acquisition; but my point is that 15x doesn't slow people down from making solid hits past 1K.
Sure I get being on a budget, but use your money wisely. If one is taking time out of their schedule, driving to the range, sending a $1.25 (6.5) plus with each squeeze... why cut corners so much?