I'm installing an retrofit Classic Air AC in my challenger.
Everything is new except the evaporator in the car/heater box.
I am about to flush the evaporator core.
After that, the plan is to put everything in and hook up the hoses etc.

The issue is the evaporator core:
If I flush the evaporator core with a flush kit, how do you make sure it's dry in there?
And do I just hook up the dryer, compressor, condenser etc and have an AC shop just fill the system with R134 after I flush the evaporator? how long do you let the evaporator sit open to dry the evaporator? or Should you even leave it open at all after I flush it?

Also, is there some concern with how long the new dryer is open to the open air or to the closed system with just air in the hoses? Do you have to connect the dryer last and quickly?
How do you do this safely?
I have the new condenser in the car now capped. the rest of the new stuff is in a box for the past several months waiting until this point.
Thanks