If you want to use readily available intake gaskets, as far as I know there are just the standard size and max-wedge sizes. If you want to make your own gaskets you can make it any size you like.

The problem with low port heads is it's harder or clumsier to make a separate solution to seal the valley. Custom manifold gaskets to seal just the ports are not that big of a deal to make or have made.

If choices in heads were slim, it might be worth it. If it was a straight forward thing to change to custom port size it might be worth it. But since there are so many head choices it might be more effective to buy another set of heads that don't need to customized and sell what you have.

If for some reason I was going to modify a head to a custom port size and location and there wasn't a solid solution to seal it all up available then I would fabricate the parts and weld it all up to seal like most other V-8 engines.