I’ve never tried 2 LNA’s in series. However, for AERO , AERO C-Band burst and STD-C EGC I have gotten a good signal with an SDRPlay (no external LNA is needed). The RTL-SDR’s don’t even come close, even with LNA’s.
For C-Band burst I use an 8.5’ satellite dish with a Titanium dual output LNBF. (One of the dual outputs is used to supply power to the LNBF). The other goes to the SDRPlay. JAERO works very well for C-Band burst.
Unfortunately there is no software for STD-C EGC that works as well as JAERO does with AERO (at least that I am aware of). Maybe JAERO could be adapted for that?