Well... my 175CDI on 20x10.5 turns at 7880 with 30/23 and about the same with the 20.5. that is with 30% Cosmo, on Coollpower 30% I get 100RPM less with identical setting (means just changing fuel, no needle or reg adjustment), I do not know the height where Christophe flies, but know he uses 25%. BTW I have never seen a YS 175 running at just 7050RPM, he might have it limited.