I have a very small CW transceiver which once produced as kit form from MFJ. This size and sensitivity is quite perfect, but it has fatal QRH issue. Indeed, even after 30 minutes later from cold start, it still floating in kHz range. This time I made a VXO circuit running from 5.94 to 6 MHz covering 7 MHz to 7.06 MHz. Eventually, this rig get frequency stability!!