Honestly, I rarely, if ever, remove the choke housings, there's no need to. The holes and passageways in them are quite large so rarely, if ever, plug up. I just pull the choke plungers out, clean them, and clean down into their hole as best I can. For float bowl gaskets, I search eBay for a good deal on a 4 or 6 pack of the K&L brand. You can usually find them for $3 to $4 each in the multi-packs. For jets I only use genuine Mikuni ones. Unfortunately, the short style Z-6 needle jet that your carb set uses is not available anywhere that I'm aware of. Hopefully yours are still OK. I think you can get knock-off 4N8 needles but the needles rarely wear out or need replacing.