On my DCC system, you run the locos round the track at different speeds, timing them with the stopwatch facility on the tablet, and the program calculates the speed matching required.
You may have problems matching the speed of the locos. The standard Hornby decoder doesn't support this feature. I don't think the Select supports speed matching either, but the Elite certainly does.
Converting locos to DCC isn't that hard. Even I can do it. There are many firms that only sell decoders, and a lot of those decoders don't come with a plug. Those businesses seem to be thriving.
I think it's ectremely likely that Hornby will be sellingb TTS decoders as a seperate item sometime in the future. They should have done so from the very beginning, but Hornby are always very slow on the DCC front.
I read a post from a model shop owner who said he made more money selling the bits and pieces than he did from selling train sets. You can't survive by just selling locos. Once a set is bought at Xmas, you need to sell everything that goes with it for the rest of the year.