Unless the 7.4 has an intentionally washed out tune specifically intended for beginner/intermediate-level skidding & sliding, Megan had a brain fart. A 2.5 base bevel won't turn & it won't carve. Most likely she meant 1 base & 2.5 side.
I'm not a pro ski tech, but I pretend to be.
All my skis, ranging from 70mm waist to 94mm waist, have been hand set to .75 base & 3 side. If your skis are new, I would suggest getting a Beast base edge bevel guide in .75 for about 19 bucks. That way you have the more aggressive .75 if you want it, and if you want to go to 1, just put a couple of thicknesses of masking tape on the stainless strip that contacts the base. Check your base edges to make sure they're not railed or flat w/ the guide first @ .75 and if you get no contact w/ your file, then check @ 1.
If still no contact, then they're greater than 1 and will be prone to skidding vs. carving and the only course then is to base grind flat & start over. But I would ski them first and see if they work ok before subjecting new skis to a grind.
Once base bevel is set, routine mtnc should not include base edge treatment. After a couple of 'treatments', you'll be cutting into P-tex w/ a resulting base high ski.
I recommend a dedicated angle-iron style of side edge guide. More accurate & reliable than multi-angle tools and faster to change out various stones & files. Suggest you spend the bucks for an all stainless steel guide vs. aluminum. They're twice the price, but aluminum will wear at the file/stone mounting face pretty quickly, and the aluminum base contact face tends to get filings embedded in it. Either 2 or 3 degree (88 or 87 degree) should work. If 2.5 is manufacturer spec, I would go w/ 3 degree side.