Cb450 Engine Re-Re-Build Gasket Question: Copper vs OEM Diameter

Amassing parts for my re-re-build, fixing all the things that I pushed under the rug first time around to get it on the road. One issue was a small weep from the cylinder head to cylinder mating. Bought a copper gasket and compared to an OEM, diameters are a bit different and not sure if will matter.

Copper diameter: 74.55mm
OEM diameter: 71.07mm

I'm sure Cappellini made them large to accommodate all the super bore cb450/500t motors out there but my jugs are a modest 3rd overbore.

Ok to go ahead with the copper?

A bit wider on the head gasket is OK on an aluminum head (which is what you have). Make sure to spray it with the copper gasket spray. I prefer the Permatex.

I second the copper spray.