Thankyou everyone for all your input. The wealth of knowledge on this forum is spectacular!! I will weigh everything that was said and try to figure out what I will do before the hot weather is here.
A Few followup questions:
1. If I decide to convert, will a system flush by a shop clean out the compressor or does the compressor need to be removed to be evacuated of remaining fluid?
2. Would the following steps be the correct ones? Assuming the answer to the above question is that I wont need to remove the compressor.
a. Have system completely flushed.
b. Replace O-rings
c. Replace drier
d. Recharge with 134a