Looking for tips...

I've charged plenty of car AC systems over the years but this is the first system I've come across that says you need to fill it as a gas, not a liquid. Apparently Sanden compressors require this procedure as a liquid fill will damage the piston or valves. So this means do not turn the cans upside down when filling as I would normally do.

So yesterday I got a loaner vacuum pump and gauge set from O'Reillys.
Pulled a vacuum for 45 minutes to insure no leaks, then started adding R134a Freon. So I got 3 cans in VERY SLOWLY. It blows cold but my pressures are still low, about 25 on the low side and 200 on the high side, with 90 degree ambient temp. Tried adding a 4th can but no change in the pressures. And I can still feel some liquid in all the cans.

Appreciate any tips y'all have
thanks,
Ron