Just forget about the below if you've already solved the matter.

It's the disk brake that decides which adaptor to use, not the fork.
Check the brand and model No of the brake first and look for the
right adaptor. It should indicate on the catalogue or whatever like
"160mm-180mm adaptor". You can probably find one on CRC site.

Make sure to choose the Post-Mount type, which is the standard
of Manitou, not the international type. Never use the adaptor of the
different brand, as it's too risky and very dangerous.

I've once done the same conversion with a Manitou fork & Avid BB7.
I got the right adaptor from CRC and it worked perfectly.

Good luck.