Hi Mark,
I have edited, literally, really a thousand drum parts. There aren’t too many shortcuts for real drumming input. Player, as you know, have a lush range of velocities (and timing), making editing a chore sometimes.
There are several ways of getting things pretty close to what you want. One is to not be to concerned about exact midi velocities, as that is gunna sound pretty stiff and not-really-a-drummer-ish. A bit loose ain’ too bad a thing.
To that end you can use the velocity change tools in the velocity editing lane; choose all snare (I’m assuming they are all the same midi note) hits and use the “scale velocity” handle to to even out the hits, and the “move velocity” to adjust the entire thing up/down without changing the relative values.
You can also use the midi effect 'compressor" in the midi inserts to limit the upper max velocity.
I’m not sure that the logical editor would be useful, mainly because even though you want to choose beats 2 & 4, they might have x-number of ruffs between them, so you couldn’t really tell it to select any well defined number of hits.
If you have not that many ruffs between hits you might consider just selecting these, moving them to a new drum sound, doesn’t matter which sound…neighboring notes works…then edit the two, individual, lines the way you like, then move the weak notes back to the snare line.
Drum editing, especially for actual drummer perfornmances, is time consuming, but completely worth it to get a natural drum performance that tight.