As above - 308L for your filler, 1mm or smaller for preference. I find that 316L is a lot easier to come by in the smaller sizes and it doesn't hurt to use that instead.

OJZ is my first port of call too, but last time I spoke to Lance he did tell me he was packing in selling bends and components etc. I have heard good things about Chris Tullet, but I'm yet to try them myself.