Turbo/Manifold Gasket size?

[dogwhistle]

So if I have an FP Black JB, they advertise the 8cm housing, so does that mean I should run an 8cm gasket or is the 16G gasket correct? I don't wanna overshoot the size and leak (like it is now), and I don't want to under size and restrict. Also if anybody knows a good place to order them for a good price, that'd be nice too. Thanks!

[dogwhistle]

http://www.maperformance.com/map-7cm-stainless-steel-gasket.html

Something like this and carve it larger? Or maybe this is correct ha. I will call FP when I get the chance. Their website listed the 6cm and 7cm for stock frame gaskets...