I cant give you the amount for a GQ but for a GU single air it is 750-850 grams and i can't imagine the GQ will be significantly different
Depends on alot of factors, temp of day, effiency of the system etc. If no sight glass start at 400g and go from there.
SorryA dial a charge only gives you gas weight by volume varied by pressure relative to temperature. 400g is 400g measured by dial a charge or a set of scales its still the same. The original post was regarding average system high pressure in relation to temp of the day etc.