Update: I went ahead and pulled the trigger on a Nikon BDC scope (the plain, vanilla Cabela's edition that's on sale for $99---had some Cabela's bucks saved up to put toward it). It's got a no-fault, lifetime warranty---so I can afford to cycle through some bad quality control product if need be. But I don't expect to have to; I have seen that they are generally reliable---for .223/.556 recoil, it should hold up fine. They're on all the Savage Model 11 gun/scope combos and seem to be quite serviceable.

I'll order a cantilever mount, tomorrow. I found a well-reviewed one with 6 screws on each ring; a bit of Locktite on those and should be set (plus, thanks to scanning receipts with the Ibotta app, I'll only pay $2 for it).