There's been a few times I've merited with Rune Chopper and Refresh Sanction (no refresh ring) and I was getting 2 MP a tic. So, you should getting 3 MP a tic with ring. However, keep in mind that the strength of the Sanction effect has to do with the Imperial Defense, or something like that. If you look up the Glory Crown on Wiki, it talks about how all the works.
Sanction Refresh is always 1MP/tick. Imperial Defense Rating simply affects the range that it will take effect in.
The main purpose of this is because I tank nyzul and doing things like Chariots make me sad. I'd REALLY love the reduced utsusemi timers. My major concearn is whether or not gaining that extra tic from balrahns plus any damage taken (ethereal) would increase the activation of the chopper above the 50% value or not.
I think it'd depend in part on how much of a base pool you have to work with, and what sort of time between fights you wind up with.
Obviously without a full 3MP/tick or better, you're going to be losing MP over time when engaged, limiting how long it'd be good for. However, if you've got, say, full MP merits, then that 80MP alone would keep the latent going for approximately the same number of seconds.
If you're recovering 2 out of the 3MP/tick, then it's only draining your base MP (well, once Sanction takes effect) at 1MP/tick, then recovering it at 2MP/tick between mobs.
Still, say, 60MP with 2MP/tick would be 180 seconds of 100% activation before you'd run dry and get the effect 50% of the time, right? Before even taking Ethereal converted MP into account.
You can get Strange Juice at the start for a 5 minute, 2MP/tick Refresh. Maybe from crates too. If you were really concerned, maybe bring some juices to use too.
I think you could make it work pretty well, provided you have some buffer MP and aren't just relying on the MP/tick to fuel it. In that line of thought, arranging gear swaps to not pull out incidental MP pieces (or put other in instead) might be worthwhile. For example, while you may not have them yet, Askar feet have 30MP on them. If you're swapping out Turban for WS, maybe swap those in instead of Hecatomb to maintain that pool.