I do play the Maus a fair bit but only ever load APHE for the main gun. I’ll give the round another looking at and give it a test the next time I take it out.
Basically the tradeoff is that it gives up some explosive filler (though 100g of TNT is not bad) in exchange for better pen and much higher velocity. So it is ideal in two situations: for sniping, especially against moving targets, it’s just exceptional, especially on a tank with very good optical commander sights; and second, to take out targets that you know the Pz.Gr 43 would struggle to pen.
In SB in particular, the higher shot velocity comes very handy.
If I’m up close and with something I know I would pen no problem if I was in a Jagdtiger, though, I just use the Pz.Gr 43. I suppose it’s not that different from the tradeoff offered by the two APHEs available to Tiger Is in a way.
I also recommend getting a custom sight: I use one that simultaneously displays tables for APHEDS, APHE, and the coax HEAT round. Very handy.
And if you tried to fire the kv2 on a slope youd destroy the turret drive and flip the tank.
Many tanks can’t rotate turret on hills, but it’s not fun for gameplay.