Start with simplest approach, try it out and then improve if in need. Any LNB brand of "digital TV" marked LNBs should have a PLL and a XO.
When getting started with SSB & CW, I do not see the absolute need for a GPS or TCXO governed LNB as long as you allow the LNB to warm up and if you know how to make minor and slow frequency adjustments in your LNB IF receiver.
My station has just this, PLL XO LNB and TCXO LO in TX converter - and SSB & CW is really easy once warmed-up. Some tuning is needed but at a really slow pace so it does not really impact SSB/CW traffic much.
I purchased the Telesystem TS100F , use it without any modification but allow it for warm-up 30minutes. It also uses the 25MHz XO and PLL and simple filtering, about 65dB conversion gain.
Being up north, also used a skiing-glove and plastic bag to make LNB less prone to temp.changes - almost no attenuation with glove and bag.
I did try to add capton tape on the filters, hoping for IF gain to increase below 700MHz, Not sure if it worked yet.
Test station in JO99 North Europe / Scandinavia
80cm dish and COTS LNB Telesystem TS100F unmodified LNB and SDR RTL USB TCXO and Sharp SW
Not optimal LNB but good enough for weaker EU stations also
LNB drifts a lot initially, but LNB has extra insulatation (a skiing glove) and after 1hour the drift is fine for CW/SSB without difficulites.
120W ERP to a Big Dish enabled CW QSO with 2 - 4dB S/N on the AMSAT UK QO-100 WebSDR -weak but QSO was possible.
Homebuild/modified surplus; exciter is TCXO xtal based 2256MHz LO, 144MHz IF, mixer 2400Mhz output 1.8mW and a 100mW MMIC amplifier to antenna system
Tests are concluded, without that 4-5m dish it is not fun, SM need more power to the antenna system. 100mW is so bad for smaller dish usage.
Maybe you can talk to the authorities to discuss moving the band limit up by 500 kHz? Or have some special status for 2400-2400.5 e.g. allowing 2W.
That would at least allow usage of the narrowband transponder.
Good idea, time will tell what can be done.
2.4GHz Highest power to the antenna system: 100mW PEP
2.3GHz 1kW time limited permit
From tests on QO-100 in JO99
With 0.1W and 75cm dish (10W ERP), it is not feasible to see or hear your own signal in BATC/AMSAT-UK 10 GHz Narrowband WebSDR
With 0.1W and much bigger dish providing ~120W ERP it is possible to make weak lines in the waterfall on the BATC/AMSAT-UK 10 GHz Narrowband WebSDR and also make CW and digital QSO
Maybe with an 13cm RX EME capable station SSB also feasible with such small ERP station