Slant questions for my upgrades.

I would say that the flanges need to be as close as possible to the same. The triangular washers can sit a little off center/angled to equalize the holding force, but not much. Good gaskets are not near as important ( IMHO ) as true mating surfaces. I'm using the standard fel-pro gasket with some permatex orange high temp goop and it's been fine for about 8 months.
http://www.forabodiesonly.com/mopar/showthread.php?t=33620