I asked Hristiyan what he would suggest, when using his transverter and 20W PA directly together.
If you have 5-6 dB losses in the cable between transverter and PA, you can use the PA without an attenuator.
But he also offered to solder a 3-5 dB attenuator on the PA board, if one uses the PA directly connected to the transverter.
Only have to tell him, when you do the payment!
Of course you can also solder an attenuator at later times on the PA board yourself!
Lead time for the 20W PA these days are 3-4 weeks.