Hi JTZ-
I coach college runners (and XC skiers) in Vermont, so imagine we deal with similar conditions during the winter that you see. XC spikes aren’t going to help you for regular winter mileage, primarily because they’re built to aid your traction during fast running (i.e., up on the balls of your feet and pushing off hard). Winter mileage should be (IMO) mostly basework which means you need more of all-around traction, not just forefoot traction.
If you deal with icy sidewalks and well packed trails the thing I have found that works best is take a pair of trainers with big lugs (Saucony Jazz/Shadow works well, Nike Pegasus also) and screw some hex head screws into the lugs. Be careful you don’t poke them all the way through the sole. You want the head of the screw flush with the lugs, not the sharp part of the screw. You can find help via google. Accumulated snow is a big challenge, if that’s what you get on your trails. For winter running in 3-6" of new snow we just go with our regular trainers and know that it’s going to be slow going and a lot of strength work. To be honest I don’t bother with the “home made spikes” much-maybe 4-5 days all winter.
As for trail running in the good weather the other 3 months of the year (haha) I have worn spikes on up to 30k trail races. You’ll hear a lot of people tell you that you need more cushioning/support for trail running over say 10k, but IMO if you run properly you should be in lighter shoes. But I’m a guy who does some barefoot running 2-3 days a week so take what I say with a grain of salt. I try to use as little spike as I can get away with for the conditions, mostly 1/4". If a race calls for less spike I usually just go with flats, and I don’t like longer spikes (3/8" or 1/2") because I’m kind of a shuffler. I like pyramid spikes in most cases. Your other options are needle spikes or “christmas trees”. I find that needle spikes pick up more debris which I personally find annoying. Christmas tree spikes are good on synthetic tracks, but I never bothered with them for trails because I’ve got a huge bag of pyramid spikes. Pyramid spikes are good all around.
Have fun out there!