Gearing reliability


I have a question of long term gearing reliability.

In a PX engine it is possible to use a 21 Cosa clutch with P200 primary to have a 21/65.
This I tried out and it works.
But I don’t have experience in the long run. Only two engines done with this and both low km.

To say more, regarding this combination you have different opinion from different specialists.
For Andi Worb of Worb 5 you can use it,
for Stoffi no,
Taffspeed no,
SIP yes…

Has some of you tried for few 000 km this combination?
Has some of you experienced problems?