Best way to keep stuff submerged for my round top square jars?

I am new to this sub, so please forgive me for asking what has probably been asked 100 times before, but I'm asking about the best way to screen a somewhat oddly/differently shaped container, and what material(s) may work best. I ferment peppers for hot pepper sauce about every 2 years, because that's about how long my "stash" lasts. I ferment for about a month, then I blend, strain, and heat to pasteurize. I know it stops the fermentation but I am going for long shelf life, and I do notice a big difference in the flavor between a month long ferment then heat and "straight off the vine into the pot". Several people have tried it and have really liked it, which is of course flattering, so this year I went hog wild on planting peppers so I could make literal gallons to hand out.
WITH ALL THAT RAMBLE NOW SAID (LOL!) - I knew my old small time "round mesh press and weight in straight mouth jars" method wouldn't make sense for the volume I'm making, so I got four 1.5gal. air lock fermenting jars. I filled them and left head room and all was well, but then I realized - I have no way to cover these to keep everything under the brine. The mouths are big and round, maybe 5.5" I'm guessing? But the jars are square. I can't keep the corners covered with my round mesh screens, and the ceramic weights just slide off. I ended up cutting my screens to try to square up the corners, but then they don't really have any corner support. Plus, they aren't very flexible, so by the time I get one corner in place and start on the next, the first one acts like a scoop and brings the solids over the top. I tried brine bags, which did help, and even though some "floaters" popped up in the corners, I have a very healthy bubble and no signs of mold or foul odors. I'm into the 2nd week so I'm not worried about getting in there and stirring or pressing down. It's just a good bit of fermenting matter, and I'd hate to lose it. Am I TOO worried about this - trying to literally fit a round screen in a square hole? LOL!