Mk3 Primary Oil?

I am just putting back together a Mk3 I purchased dismantled and as I haven't owned a Mk3 since 1991 [recently I sold my MK2A] am interested in your comments about primary oil, I have read here that ATF is a no no, and actually in my other bikes I have been running Maxima MTL 75wgt which is a 2 stroke gearbox oil equivalent to a 30wgt engine oil, but am unsure what to use with the primary chain tensioner.

As I understand it, the tensioner needs oil, as in normal motor oil type stuff.

But don’t forget that your clutch is in the oil too.

So, any motorcycle engine oil that is designed to be suitable for a wet clutch should be perfect.

There are dedicated primary oils on the market which, one would assume, would be the best choice, but I‘ve never used any of it.

I used to use 20-50MC oil and always had a bit of clutch drag. The last time I had it apart I reached for a bottle and found it empty so I used what I had in the shop - Rotella 15W 45 diesel oil. Amazingly I now have neither clutch drag nor chain slap so everything seems to be happy with it. It's just my experience so take it for the anecdote that it is.
I've thought about ATF but on consideration I'll not mess with success.

ATF is about 5W, perfect for chains and clutch but not the tensioner.

I use the same oil I use in the engine in 2 x Mk.3s Bel ray EXP 20w/50 and have no issues.