I am sending you the files of the PCB designs that I made on EasyEDA as I promised. I am not an expert on making PCBs but the files I attach work well for me. I ordered the PCB boards from JLCPCB and I was pretty satisfied with the quality.
Since I do not wave a signal source with more than 4Vpp to drive the exciter, I included a simple 2 transistor amplifier in front of the CD4013 (or CD40106 in my case).
I am sure that the designs need further optimization but I think it would be very helpful for someone to start with the construction of the transmitter.
I also attached a photo from my final assembly.
Feel free to make any changes if you wish!
Best regards and greetings from Greece!
P.S. In case that there is a problem with the format of the attached files, please let me know.