I've had a chance to fly a 19m Venom2 and 15m Syn.

The strange thing is I still couldn't quite "get it" (speed, lift, placement in the window) like I did immediately with my 12m Phantom - (whose power and lift comes more from speed, I guess).

I realize that these later (and bigger) Arcs have more settings and a lower aspect than the earlier Phantoms. But maybe simplicity is good too.

Are there any tips for setting and flying these to make a possible transition from a smaller Phantom?

Make sure that the internal straps are all tight so you get full power and fast turning. That will help.