Hello again to the forum,
i've got a recently installed rural link with junk found around town, more to test the feasibility than production, but in the end it stayed that way and operating successfuly.
i have sxt lite2 on one end (AP side) + mikrotik metal2 with 24dBi grid on the other (client side), 4km over a hill and over a forest (or thru the forest, not sure as i don't have LOS, it's going thru some trees that's for sure).
so out of this piece of junk i managed to get ~35mbits of real life speed that are quite stable, and got internet to a rural house that otherwise was stuck on 2g mobile (rarely 4g, when i tested i was getting 0.5 - 1mbit download and about 0.01 upload).

since this setup is really ugly (grid is about 20 years old, all rusty) we were thinking to replace it with something newer. we already have a satellite dish that is not used (90cm) and is in good cosmetic shape so the idea was to buy LDF2 and use LDF with that 90cm dish. maybe that way the other chain would also work?
does anyone know how much gain a combo of LDF2 + 90cm dish would have? LDF is as cheap as it gets, locally available for 30eur.
this is the current signal:

Yes, LDF2 will be able to use both chains to SXT unlike Metal that's limited to single chain.
I'd say go for it, LDF is cheap and with 90cm dish you get ~25dB of gain by antenna alone + the two chains.
You have enough SNR to probably run 100Mbit/s real throughput if both chains are used and there's enough power.

i must say i'm impressed.
for test we put up the sat dish, and with a zip tie mounted sxt lite2 on the lnb holder. after some aiming, i got -67dBi receive, and speed is 100mbits on 40mhz channel.
i ordered the ldf just so i can fix this more firmly and long term. can't believe that thru a forest i'm getting 100mbit at 4km.
also, it's 3-4 dBi stronger signal than with a 24dBi grid, so that means this sat+sxt combo is ~27dBi gain?

It's likely your original dish was less than 24dBi (they are often overrated) or there was some additional loss in N connector. Using LDF or SXT is far more efficient (no cables with loss, all is integrated on a PCB). LDF should be even better than SXT as it's optimized to illuminate offset dish exactly.
And it's nice to see someone else is having fun with using offset dishes for wifi links...

so that means this sat+sxt combo is ~27dBi gain?

No, that means the signal's about the same. Metal has one channel with -71 on SXT with two channels with the same level, and two channels is plus 3dB.
There is one flaw in your metal data. The signal level from SXT to metal is -62dB and from metal to SXT is -71dB. By equalizing the signal levels you will get a more stable channel.
For stable operation with maximum speed in the 40 MHz band you need signal -61 or stronger.
When configuring, do not forget to look in the specification, what speed at what power can provide the device.