phil wood lockring. I meant I'll ride my soma until I figure it out

DA stops at 16t though right? Hopefully the problem will be solved when my PW cog comes in, but I would like to know which ones I can get away with using. I don't exactly want to buy a 19t in PW and a 17t in PW if I don't have to. I'd like a 19t for easier riding, the PW is 17