i don't use an o-ring - is there a need? Not tried SS mesh in a reomizer2 yet. Normally it's in a genesis tank. I am rather impressed with super-x's micro coils and Kaypers use of cotton wool balls (well - any old set of balls really) because it's easy.
I have used it in an A7 before and it's rather dodgy. In Nova tanks i use it, but HRH has preferences i must adhere to - so i still have this PITA - wrap 4 coils etc... Such is life.
T