[ihc] head gasket advice

[<spamaddy@xxxxxxxxxxxxxx>]

I'm going to tear my IH 345 apart, and since I've never done anything like
this before I thought I'd seek some wisdom from the group.  I've read
through the shop manual and have a pretty good idea what to do on
disassembly and reassembly, but is there anything I should watch out for in
the process?  Any "gotchas" or tips from the veterans?  Any lessons a
first-timer should know?  I usually learn the right way by doing it wrong
the first time, but I don't have that luxury this time.  

Where's the best place (or brand) to get a head gasket?  Can I just buy the
one Napa sells?  Should I buy a new gasket from a light line distributor or
perhaps somewhere else?  I know there's a concern about the thickness of the
head gasket, and I'd like to avoid any milling of the heads if possible.

Should sealant be used on the head gaskets (like the copper-gasket-spray or
"Indian head" type stuff)?  Should a sealant be used on the intake manifold
gaskets or the exhaust gaskets?  Any and all advice is welcome!  Thanks!