Is this facebook forum still active? I've tried joining the group several times but my request to join is never accepted. If so anyone know the forum moderators who could approve my request to join?

Be patient, the admins only approve new members every couple of weeks. You will get plenty of advice if you ask your spitfire question there.

My take, you need more board speed and less angle of attack (more gentle, flatter quicker pump) when pumping up on to foil. I have an hps980 and similar experience to you when I first got it (after moving down from a very big foil). You could also try a bigger stab, if there are other axis riders in your area you could borrow a p400 for a couple sessions which would help stabilize the pump and takeoff. If you are in the Christchurch, NZ area you could borrow mine!