My MLA-30 is collecting dust. I never really it used for much.
I installed a RCA connector with a F adapter at the preamp to use RG-6. It was probably whatever I had in the bulk connector parts box.
Also I removed the USB connector and bypassed the potentially noisy 5v to 12v voltage converter in the bias tee. If nothing else it now works fine with a 12v PSU or even just a 9v battery if preferred. I probably should have added some extra filtering caps in the bias tee just to cover the bases, but "whatever" I suppose. Think I potted my bypass mod with hot glue anyway, as I ended up soldering the positive side to a copper trace on the PCB. o.0
About mounting height, that is more a concern with horizontal loops due to ground losses, unless you are explicitly designing a NVIS or loop-on-ground antenna.
As for a vertical loop, you might consider localized ground clutter when planning the deployment height to maybe improve low-angle performance, but even consider that a huge YMMV depending upon ground conductivity and a myriad of other issues.
Best approach IMO and as noted previously here, move it around to find a hopefully nice low RF noise location, as improving SNR will tend to net the most gains for such an antenna. Moving a small loop, e-field probe, or similar antenna a few feet sometimes can make for a considerable difference if in a high-RFI location.