I also use the Diavolo-Twin-LNB. Fits nicely in the duo feed from https://uhf-satcom.com/blog/patch_antenna.
For desoldering the smd XO it is not necessary to demount the pcb from the casing. Hot air station 858D+ with 470°C and fan 6 works too. I have made 2 LNB's this way without problems.
On the signal pad of the smd XO I have used 820pF. On ground pad I have placed 50 ohms in parallel. I use a Leo Bodnar dual GPSDO with lowest singal strength at 25 MHz. The other GPSDO port feeds a pluto sdr at 40 MHz.
The lid of the lnb casing easely cuts the red wire in the picture. This happend to me more than once. Keep the red cable away from the RT320 an its singal traces. This could cause RX interference.
73 Harald, DL3HM