Thanks to all those trying to help me. Short story was that I was able to get my BTech GMRS-V1 to speak to my Midland GXT1000P on one of the "present channels" (e.g., privacy codes); it was between Midland channel 31 and GMRS channel 2 using DCS 1 (D023N). I tried on three other setups (per Midland's instructions) with no success, although, on at least two attempts, the Midland would light up and show "RX" but without sound when transmitting from the BTech. Apologies for the poor photography.