seriously speaking, HLG is easier to implement than DV, just metadata, not dual video stream or so.
what i don't understand, razorback, is how you set up the video line; isn't the tv decoding directly the satellite signal, using internal tuner? where are you recording streams, external hdd? (i suppose that those recordings must be encoded and playable only on recorder tv).
anyway, a sample could be useful, if you can provide one.