I will post more later, but I am not liking Rest/Bulk Up. I presonally like Recover/Substitute, as it blocks status and provides recovery without that 2 turn waiting period. It also allows you to use Focus Punch, which is better than Stone Edge you shouldn't bother going against Gyarados/Salamence regardless, and doesn't have 80 accuracy.
Also, you should run Curse and Crunch/Payback on that Tar, simply because factoring STAB and the boost from curse and either the power increase in Payback or the defense drop from Crunch will mean that Tyranitar wins regardless against Heatran.
EDIT: Flygon does resist Fire what are you talking about? o.o
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