Sounds like you are doing fine. I used an ACM evaporator (with expansion valve pre-installed) and had no difficulty with the underhood lines. But I suppose every job is different.

Can't picture the screws you are having problems with. I replaced all the vacuum pods, but don't they just rotate to release the tabs, and then pull out of the mounting brackets? Or am I thinking of some other car...

Try Lowes or Home Depot for heater hose. My local Lowes has a huge variety of rubber & plastic tubing in the plumbing department.

- JimY