Sounds like the low end is lean.
I think a lot the Magics have a bit of a "first start" problem, though they aren't that bad.
The "very tall" mains place the tank outlet FAR below the carb. Mine always gets
fuel by the second flip though, if I have a finger over the carb or muffler outlet.

Which again leads me to believe your low end is a tad bit lean.
Open the low end adjustment 1/8-1/4 and re-tweak the high end when you get
it warmed up, just like you have it now. (300-400 off peak) Then fly it again.

Just remember where it was, to put it back if you don't like it any better that way.


Having a lean low end, combined with anything that would throw fuel "away" from
the direction of the carb, makes it tougher to draw fuel. Sometimes a fatter
low end will help. You might also check that your muffler seals well, and that
you have no leaks or kinks in the pressure line to the tank. (or leaky tank?)
Maybe even a one way checkvalve in the pressure line might help.
But do try the simple stuff first