I completely agree with PLK. I coach a team of 30 single ply lifters, a few of the things that I would say are based on who you have with you team wise. If you don't have a few folks that are versed in gear or specifically single ply gear you definitely need to go slightly looser. When you get in fully dialed competition gear you're talking about very experienced lifters with a good support group of spotters and folks that understand how to set gear and how to ensure your form is dialed first. Super tight gear will crush your form especially for a person just starting I've seen it over and over again. Squat suits too tight will buckle your knees you don't want that. The bench shirt will become a dangerous nightmare as you will come out of the groove and possibly take a bar through the face. I'm not saying wear loose gear I'm saying do not go tight first, just my opinion.
Second, I'm a multiply guy except with my deadlift suit but I'm a conventional deadlifted. As far as which gear to buy I'm sure any will be a great place to start but in single ply, I think there is only one choice and I see it with my team Titan gear is freakishly superior (again my opinion). I think they are getting away with some shit LOL their material, stitching and design are almost not fair. If I was going to compete in single ply I'd get Titan gear shirt wise I'd get the Super Katana if you have a good arch they have a version that kills if you don't have an arch they have one for that.