Engine oil ct70

Hi, every one. Restoring my 1970 CT 70 and starting to think which oil would be the best. I read a lot of info about this and reduced my choices to 3 different types:
SAE30 mineral Rock oil classic JASO MA/MA2, API SL, API GL1-3 non detergent
10W40 mineral Rock oil Gamma JASO MA, API SG
10W40 part synthetic Castrol power1 4T JASO MA-2
My question is, shall I go for
- the classic mono grade recommended by the manufacturer for this engine back in the 70s,
- the slightly newer multigrade version but still mineral,
- or the new semi synthetic Castrol option
All of them are safe to use with wet clutches
Although the classic was recommended at the time, I can't help thinking engine oils have improved over the years and was wondering what you guys thought. Conservative, middle of the road or new age?
Thank you
Phil

I'm interested to hear people's thoughts on this. I run both my 1973 Dax and 1975 Chaly with Castrol Power1 without issue.

got the new stuff too, castrol P1.
Bit of a sleepy forum, but thank you for your reply anyway