Rebuilding engine/ head gasket compression question

alright... i am rebuilding a 360 for my duster and have a few questions. I want to keep it cheap, but keep it so it will run strong for a good 5+ years until i am out of college and finally get some money to pull it and build it the way i want. I am sticking with the stock pistons and am planning on having the machine shop re ring them and put new bearings in. clean and test the block and rework the crank if neccisary. i'm also going to have the valves back cut and bowl port the j heads to increase flow a little bit. I have heard of getting thinner head gaskets to increase compression a little bit. What am i looking at for an increase and any suggestions on size? will the thinner gaskets be much less reliable? any other suggestions on how i can build a better engine? I am looking mostly for suggestions that will be affected while at the machine shop.