Rattler -
the Testastretta engines are more powerfull indeed and are happier revving and have lost a bit of that all out grunt of the SPS long stroke engine.
So logically thinking you should indeed lower the gearing to make the most of that engine even more so on the Testastretta than any SPS and BPs that you might have changed before.
The impact on top speed down the straights shouldn't be as critical either because the engine revs better.
Please make sure you advertise your first day out on the bike. I don't want to miss that!!