[Collins] Question: Best KWM-380 Final Transistors

[LeeCraner at aol.com]

I am in the process of replacing the final transistors in my KWM-380 (sn 
10xx).  The rig had S-100-12's originally installed. I have a match pair of 
SRF3662's coming from RF Parts.  

A scan of the Collins reflector archives listed the following transistors as 
OEM or reasonable substitutes for the finals in the KWM-380:

CD4242
MRF421
S-100-12
SRF3030P
SRF3662

This begs the questions:  are these all interchangeable?  Is there one or 
more of these better than the others?  Are there certain ones that should be 
avoided?  Any other numbers that should be added to this list?

And, while we're on the subject, any hints or cautions on installation or 
getting the maximum life out of the finals?

Thanks for your input and collective wisdom.

73
Lee WB6SSW