As 90,000km looms on the odometer, with most of it spent hauling a chair I suspect, my XS is acting more and more like an automatic

I have just searched for threads on clutch replacements, but while it is clear a few have done them, there is nothing that answers these questions:
- Should I go stock or aftermarket?
- If aftermarket, are any particular brands recommended / not recommended?
- Where to buy?
Obviously I could (and have) searched the web, but I'm wondering if there is a local source.
- Is the RH clutch different to other XS models, or can I just buy any XS11 clutch kit?
(Important if buying from OS)
- Any mods or other jobs I should do while I have the clutch housing open and plates out?