Hello. I had an Sig Mk IIa SE line stage a few years back and now have a Master with phono. I rolled the 6922’s which I would recommend that you do first if you haven’t done so already. I found Mullard’s to give a warmer presentation. Amperex tubes are more neutral. I ended up purchasing NOS Telefunkens. They’re neutral, detailed, present a nice soundstage, extend high and have tight and accurate bass. I liked them so much that I purchased medical equipment grade Telefunken 12AX7’s from Brent Jessee recording. His website has tons of info about 12AX7’s and 6922’s. He’s also very responsive to emails and can provide guidance based on your listening preference and budget. Regarding 6922’s, I purchased matched cryoed Kevin’s stash ones from Upscale Audio.
HTH. Happy listening.