parallel condensor and AC system work - advice request

[JHZR2]

Hello,

My 85 300D has no charge in it right now, and is still set up for R12.

Whether in the end all I go for an R12 fill or an R134a retrofit (which at this momebt Id likely prefer because of cost and self-servicability), it seems that a new parallel condensor is the smart way to go.

Now, given that the system is 22 years old, still has the original compressor (which works when jumpering the low-p switch), and likely the original oil fill, it seems to me that when the system is worked on, the whole thing will need a solvent flush, etc. prior to closing up and charging.

Given that the parallel flow condensors do not easily flush out, and given that I do not know much about AC work, my question is this:

in the interest of getting what I want, saving a few bucks, and learning about my car, could I purchase the new condensor and install it prior to having the system worked on professionally?

My concern is regarding them working on it by doing the flush, etc. Id hate to have a new condensor ruined by installing it prior to having the system flushed and prepped for r12 or 134.

So, in all, is it smart for me to buy and install a new parallel condensor prior to having the pros go over my system, flush it, determine their reccomendations for r12 vs 134a, etc, or should I just wait until they hav e the car, and get them to install this new condensor after doing other work?

I am not aware enough of the actual order of steps generally taken to know what to do off the top f my head.

Any advice would be appreciated.

Thanks for reading my long post!

Best,

JMH