This is not possible, as the Tripletuner in fact is a Single Tuner, to which you just can change the mode to C, T or S2. But only 1 at a time can be used.

To have a Dual tuner, you need to use the normal Tuner board (or this TestTuner named TripleTuner), and put for example a DVB-T or DVB-S2 tuner on a USB Port. Then you will have a real 2 Tuners.

There is also the original Dual Tuner S2 available, with Japhar Drivers for the DM800HDse. Perhaps this is the best option for you (Si2166B Dual Tuner DVB-S2, if you want C/T2 you have the Hybrid Dual Tuner - Dual Tuner, DVB-C/T2).

I don't know how works the "Scr Unicable", some are capable of receiving few streams from different frquencies with 1 tuner only, but this is in fact the LNB capable of doing so, not the Tuner.

TS