I understand all that work is needed to get at the coils to clean
them, but to me its not worth the trouble, plus you risk damaging your
coil trying to make some kind of access to get to it. If you ae going
to go through that trouble, wait until the A-coil craps out and
replace with a new one.

I agree with the other poster. If there is at least 17-20 degree or
more difference in the return plenum and supply register, the system
is fine. And if the return line of the refrigerent line is cold and
sweaty, thats a good sign too.
If your house gets to the proper temp with the compressor regularly
cycling on and off throughout the day ( about 2- 3 times/hour), I
would leave well enough alone.