FC Roof AC drain tubes for new units

[hifreqdude]

Hello, I am getting ready to replace the original ac units on our 78 FC with Coleman 15000 BTU Mach 8 low profile units.
My question would be to anyone with previous experience routing drain lines weighing in as to solutions.
I did read a thread wherein Randy Dupree indicated running lines to the vent stack, which I thought was a great idea, but I am thinking of using units with the condensation pumps and from what I can tell they come out inside the unit opening.
Should I just buy the standard units and affix a drain apparatus to the vents, I am pretty handy with many things and know i can figure it out on demand, just looking to expedite a plan or draw from this deep well of knowledge here before pulling the trigger, poised and ready.