You can run A1's on HP - but not everyone can get the velocity down if they do. Depends if you want to take WDP's advice or not
.
From page 6 of the manual :
"The Angel is designed to operate on air/Nitrogen gas.
This needs to be supplied to the Angel at an ideal
pressure of 400psi (27.5 bar) using a suitable first
stage regulator."
Anyway - money sent. Looking forward to the postman ringing now
.