Engine HEAD GASKET HELP !!

hey so I found some coolant in my oil. (hope for the best prepare for the worst)...
upon tear down, everything was in order except for the head gaskets. the block is O RINGED 306 sbf, trick flow twisted wedge heads, wolverine cam, vortech v1 (5-8) psi.
i found that the head gaskets he used were not made for O RINGED blocks, hence the coolant in the oil and in between the deck and heads. upon further investigation...
I called ALL the gasket companies and they all said the same thing. take out the oring and run a MLS from either COMETIC or FELPRO. spray them down with copper spray before and youll be good to go. i found some old posts from about 10 years ago on this topic and they all seem to agree with this plan of action.
is this still the way to go??? I dnt want to tear down the block again if I don't have to. ( atleast not for the same issue). this will not be a track car, and in fact will probably see very light street use in the spring and fall. (no AC no heat) so if i go the recomended way, my question is

1. what bore size gasket should i get? (shes a 306)
2. what thickness should i get?
3. fel pro or cometic (even though both say not to use with oring reciever grooves around the bore)

ANY info on this topic would be greatly appreciated as i would like to start building her back up asap. thanks guys.

hey that sounds good. engine is out and on the stand. shes a 92 im swapping into my 86 notch. im trying to avoid the machine shop since the motor was rebuilt about 5 years ago and was barely run since the rebuild. maybe 20 miles. (luckily, or else there could have been serious damage with improper head gaskets). upon tear down everything is clean, like machine shop clean. pistons barely have any black on them same with the cc on the heads. the coolant on the deck and in the oil was the dead giveaway for the heads gasket being the wrong application. I know for a fact it came from a machine shop that did the rebuild, kinda messing with me that they used these gaskets. a mistake?? maybe... a last minute, "lets get this thing outta here"?? maybe.. so I really just want to clean this thing up and replace what I need to replace and continue on with this build. def not trying to cut corners just trying to avoid machine shop at all cost. $$$$$$ I know the spec for the fel pro 1011-1 is 4.1 bore .041 thickness. iv never really looked into sizes of heads gaskets before just used what was recommended for a 302.
is 4.100 bore gasket to large for a 4.030 306 or is that just a normal size to use?
should I be using a 4.030 bore gasket instead?
same with the thickness, is .041 a standard thickness for 4.100 bore?


also I didn't mention it, but all those threads from 10 years ago all pretty much all said the same thing. remove the o ring and use a COMETIC MLS. they all used that method and had no problems to report.

I really appreciate and all info, thanks so much.

THANK SO MUCH GUYS!. all this info is great. so I cleaned the block and heads up and checked for warpage and we are all good. im gonna pull the o-rings out and just run the MLS gasket. does any one have a recommendation for the thickness of the gasket.?? I know .040 or .041 is pretty much standard, but do I need it to be a little thicker so as to fill the receiver grooves around the bores??