To save you time and trial and error. Use the following and only the following:
1. Stihl chain.
2. Stihl files.
3. In your case use the 7/32.
I've tried other brands chains over the years and when I used stihl chains, I never bothered with anything else. They hold their edge
far better than Oregon or husky chains and you need their extra hardened files to file them. When I have tried another brand a time or two again, over the years, I was always disappointed. I've been running only stihl chains now for, I dunno at least 15 to 18 years I guess. It didn't take me too long to try them on my huskies, due to having a nearby Stihl dealer. It was probably just dumb luck and I was working nearby and looked in there to see if they'd have a chain for my husky. I'll never bother with another brand chain. Stihls are the
absolute best.
The reason you want to go up a size file is because it sharpens not just the cutter side edge, but the top part of the cutter too at the same time in same stroke and you'll get a sharp, factory like cut.
Here's a simple little photo I grabbed off the net. See the little circle I added in red? If you use the called for size, your file will just fit down inside and get the main part of your cutter nice and sharp no problem but if you don't go back and take another stroke while holding upwards on the called for file, you wont hit that part I circled, see? That's why you'll never get that same "brand new chain" feeling while cutting again, even if you (eventually, once you file the chain a few times) bring your rakers down or get a nice perfectly sharp cutter again. If you miss that step, she'll never feel like factory new again. So two options to hit that; pull up a stroke or two on the called for file size to hit it, or cheat and use a size up, in your case (and mine, with my 372xp) use a 7/32 and while sharpening, the oversize file will hit them both. The side and the top and you can regain that factory, brand new chain cut!
View attachment 968894
For us 372xp guys, it's easy. Just remember to grab a 7/32 for that 372.