Wow Kev you got your hands a bit full....
Being that you have a 95 L27 I recommend that you replace the upper intake, when you remove the upper intake you will understand why, could also be a coolant consumption issue or part of it... Both Dorman and Delphi make a replacement for this..
The lower intake gaskets.... I would recommend Fel Pro for those... There is nothing better for the L27 TPI then what they sell...
If you are going to dig into this let me know and I'll toss in some pics as there are some things I would want you to do for a good seal and a dry motor...