There used to be 0.3 head gaskets but they seem to have disappeared from supply.
1.15 squish is not so big. Not ideal but ok.
Option 2 might be worth a go as it's easy. 129 is quite a bit but could work. Now the exhaust is changed would make an interesting test. Will go better at WOT but pulling 4th is the concern. Was it ok on the bad exhaust?