Couple questions, all about bolts.

Iron heads generally do not need a retorque although it might be cheap insurance if you're using a steel head gasket. Aluminum should be after a couple of heat cycles, regardless of gasket type.
If you're having leaks there are a few possible reasons:
1. The surfaces were not 100% clean and oil free, including oil from your skin, when you applied the gaskets or the sealant and gaskets. Everything should be cleaned and wiped off with brake clean prior to any assembly.
2. There is a problem with assembly or machining causing excessive blowby.
3. You do not have a functioning PDC system.

I actually prefer studs in the end holes on the iron heads. They tend to seal better and once installed they stay put so the sealer doesn't get torn or loosened.