I have no experience with Henry. I have had two TE UHF and one VHF amps. I have only used them on SSB and they do not have the repeater heat sinks. They are clean looking inside and out. They usually go into gain compression before reaching the max rated input power level. The output power usually drops a little as they heat up. Output power is typically on the low side of spec. Even on SSB they get warm and need fan cooling. My reliability has been good but I keep hearing that you don't want to send them back to TE for repair but there is at least one other person that will do repairs on them.
If you track how the output power changes with input power you can tell where the TE AMP starts to go into gain compression and that is where I would stop the drive power even though it will probably be less than the rated input and even though you might see a few more watts of output power if you keep increasing the drive it isn't worth the risk of blowing it up. John Lock kf0m at arrl.net
