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

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...

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

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.

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

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.

II asked my distributer to check with Rega.

In the meantime, as advised above, I will close it very gently just so it does not move.

I remember that Rega used to sell a torque wrench set for their cartridges.

depends on the cartridge body undergoing deformation under load . Common sense is a good guide..

Per Rega the Aphelion 2 torque is (0.4 Nm)

You might want to ask the distributor in your country (or closest country) for info on the Apheta 3. 

Here is a list of global Rega distributors: Rega Dist

When it comes to cartridge bolts and torque - less is more.

You should just nip them up gently - too much torque can distort the cartridge body and impact sound negatively - at worst damage the cartridge.