yeah I really think 40mg was the ideal dose for me! Strength increased much more after the 40mg, I can train also much harder now..
I really was surprised of the difference of 30mg and 40mg.
When I was on 30mg I also got increased power, and I 'felt' the Havoc. And almost had no sides (except for headache and backpumps)
But when on 40mg, power is increased much more, it's really a big difference..

But on the other hand: I really had to get enough sleep, make sure to I got plenty of extra carbs, increase the taurine,... If 1 of those factors was not 100% ok, I felt horrible. Certainly the first days lethargy was an issue..
I think the best is to just try the 40mg for a few days. If after 3-4 days you're still feeling not ok, then go back to the30mg..

It's certainly worth trying