I just finished a project for a special Pluto and QO-100 GPSDO.
It delivers three frequencies: 40, 25 and 10 MHz.
You will find the description of my creation here:
In French, but I have no doubt that google will offer you a correct translation.
If you haven't forgotten to use the soldering iron, this GPSDO is very inexpensive.
I will investigate the possibility of having at least all SMD components mounted.
To be continued.
73, Lucien F1TE