setting the mast rotation for a-cat like wingmasts:
http://www.landenberger-sailing.com/spip.php?article21
link
Important point is to accept not to have a smooth lee ward surface in some cases.

For non-wingmasts I agree with the rule "using downhaul first, then rotation".

Wingmasts are rotated some 30...40° more to the centreline than conventional masts in general.

Cheers,

Klaus