If I may, couple of tips that take seconds but will make it sit/look way better. The main thing is, if you haven't already, clip your gun in and test that sling, like hover the muzzle just above the bed and give it a serious yank to check the security, seen more than a few gats suddenly drop when airsoft single point slings with a 1" buckle haven't been up to the task. If it fails or feels borderline you'll be better off just relying on the carrying method god/evolution gave you vs thinking the sling has got it when it doesn't.
Some cheap foam cut to fit inside the plate bags will add basically no weight and won't hinder but again, the rig will probably 'sit' better and it'll certainly look a lot better; more like the look folks envision in their heads anyway I believe. Obviously you'll have adjusted the cummerbund for your waist, but most people generally leave the shoulder straps too long. It's only airsoft, as I've said before it's not the end of the world, but generally the top of the front plate want's to sit where your collar bones meet in the middle. Some things to consider anyway.