Rega Apheta 3 on Rega Planar 8:  Any idea on screws torque values ?

Rega does sell a torque wrench. It's $275 USD. It's included with their Aphelion 2 cartridge but available separately on Music Direct and other audio websites. I don't see it listed on the Rega website however.

Just talked to Rega. Apheta 3 is also 0.4Nm.

instead of spending $275, just follow dover's advice and it will be a lot cheaper without any other compromise. 

second instruction of that cartridge somewhat amused me about cartridge bolts... are the wires of the cartridge that badly exposed and lose that they can potentially reach mounting bolts??? that's weirdest design perhaps.

275$ is way too expensive but 99$ for a Hazet is reasonable ...
 

An even better bargain for a quarter of the Rega price but double the quality:
A german Wiha fixed 0.4 Nm torque wrench.
 

czarivey and Dover,

I'm totally with you as far as using my watchmaker hands but for 80 Euro including shipping and after I had the incident with the test LP that destroyed my Apheta 3, I'm really not in the point of taking any risks...