i've used a 16v HG on a 20v rebuild, there are minor difference between the 2 gaskets though, by memory small coolant hole differences. though i saw no harm in this.
a VRS is normaly every gasket from the head gasket up. if they sell you a VRS for a 16v, it'll be no good for a 20v, different cam cover gasket required etc.
the rings you will need to measure the ring gaps on the pistons, if the 1st one (top) is 1.2mm, 2nd 1.5mm, and the oil scrapers 2.8mm then you use the same rings as a smallport 4age piston which in ACL is part number C1806.STD (STD for standard bore, not oversized).
if however the top ring gap is 1.5mm, then the C1741.STD ring kit is required (same as a bigport piston).
have fun with the rebuild.
p.s. i buy 0.8mm gasket paper and make my own oil pump, rear main seal cover etc. gaskets, and seals needed seperately. it saves a lot of cash on gasket kits!