Let's address a number of things that could help solve your issues.
I don't know what a "fond thick gasket" is. What brand and part number are we talking about?
Using two gaskets won't help at all and will make things worse, doubling your chances of a leak. If you don't have one, get a RemFlex gasket set for your intake/exhaust. They are expensive but worth it.
Are you following the torque pattern in the FSM (you do have one, yes?) to tighten down the manifolds? When I do a torque pattern, I do it in thirds. If it calls for 60 lbs on the bolt, I do the entire pattern at 20, then 40, then the final 60 lbs. The manifolds get very little torque, don't overdo these!
Are you using all the correct hardware, and are the special washers oriented properly?
If your intake is old, and the exhaust is new, it's likely they won't match up well. If the manifolds are all wonky to each other and not true/flat, no gasket on the planet is going to help you out. Best bet is to mount them together as close/true as possible using a straightedge, tighten them up, and then take them to a machine shop to get the mounting surfaces trued up. The guy that did mine used a gigantic belt sander to flatten and true the two to each other.
Others with more experience may jump in to help here, but I don't think Loc-Tite is the product you want to seal a stud going into a water passage. I used Permatex 2 on one head, and The Right Stuff black on the other. Neither one leaked a drop. Did you chase all the threads before assembling everything? You need to make sure all the old crud is out of the threaded holes in the head before assembling the new studs - and everything else.
