I can vouch for what 009 is saying.
The cross-over rod that controls the lever to poppet mechanism and hence the lever free play/height, is a bit tricky as the rod spins when you try to adjust it.
I got round the problem by adjusting the poppet end first to stop any hiss then 1/8 of a turn (on a new seat), nothing on a reused seat, and then adjust the lever height by holding the rod with a pair of thin long nosed pliers at the lever end of the tube, while adjusting the 1/4" a/f nut down the hole with a specially modified (ground down outside dia) nut spinner.
The settling in of the rubber puck/seat moves the whole assembly over to the hose side and lifts the lever so if its set too fine the lever hits the diaphragm and it starts to hiss at best free-flow at worst.
The good news is that once set AND bedded in, the adjustment then holds its setting for the rest of the year. The rough and ready (is that cheep and dirty in American) way to set it is to have the lever set too low so that the reg "rattles" after assembly but that means that the reg doesnot open fully to give you maximum amount of air in use.
I hope that has you on the right path. PM me with a non-forum email address and I'll send you an exploded view of an Arctic/ parts list...
Brian C