Have you had a problem with them in the past.....the AGA kit ones?......I had to tighten mine once or twice as the gasket compressed on installation, but never had a problem....In fact I would think the glass would crack from too much shear on the edges first if over tightened before leaking.....been my only concern.....If yours are loosening....you could put locktight on them.
I find it hard to upgrade this stuff sometimes, because I don't think its neccesary.....ie not under high pressure or vibration situations, pushing the envelope of the design,......though piece of mind is priceless.
I agree, the AGA kit is overpriced, but is a simple kit with easy dissasembly and I like the way you can adjust the water height...I have heard people that have water noise with them....but mine seems quiet enough......its the skimmer that kills me!!!!