2rz copper or mls head gasket

[ra22turbo]

I have a 98 2rz that I want to install ARP head studs and a thick gasket in order to lower the compression ratio. my questions are where can I find the thickest gasket , and what material is better copper or mls ? Another question I have is if the engine never overheated do I need to mill the deck of the block and cylinder head or am I fine with just cleaning the mating surfaces? I was thinking about stacking two .50 mls gaskets and stacking them or a .90 copper gasket?
Last question is do i need to oring the block in order to use the cometic gaskets? Thanks in advance I apreciate any and all help. Thanks

[jdzumwalt]

do not stack gaskets cometic will custom make you one thicker.

[ra22turbo]

Thanks for the heads up . I appreciate that..