I know a solution for all arty...make it load HE first, with AP as simple a secondary round |: They shouldn't have much AP anyways...the Wespe only carried 8 rounds of AP.
If anything should come out of this thread, it's this.
Artillery users rarely use AP rounds, it should most definitely be the secondary round and NOT the default round when entering. Precious seconds are lost when you have to select change the rounds.
The only argument I see against it (which is valid) is consistency between vehicles and artillery so HE rounds is always no.2 no matter what you are using.
Still, despite the consistency argument, the focus should be on a streamlined user experience, something which FH2 is seriously lacking in some areas. Considering the delay from entering a artillery piece, changing camera view, zero'ing in, and being able to fire, I don't see this an unbalancing in the slightest.