My clubs Lenz sets use the Magna force MF615. On page 20 of the LZV100 manual there is a list of recommended power supplies. It is best not to stray from the recommended list. Keep your MRC power packs for layout lighting or the train running around the Christmas tree. Do not use them for powering your expensive DCC system. You will have problems with not enough power for the breakers to trip when a short happens.
The output specs on those MRC power packs indicate 17 Watts output for the Tech 4 Railpower 250 and no output rating listed for the Tech 4 260. I don’t think either one is suitable for use as a DCC power supply. You need a transformer with at least 5 Amps output at 16-19 VAC, which equates to a power output of 95 Watts (Volts times Amps = Watts).
Using a low powered transformer will cause the Lenz system to perform erratically if at all, and the transformer will get dangerously hot if they don’t have the proper internal thermal circuit breakers…
I ran my Lenz Set 100 for quite a while on an old train transformer. It worked fine, until I added some illuminated passenger cars and I was running sound engines. Then I noticed that everything ran very slowly. I’d run out of power.
I bought a 5-amp NCE power supply and I’ve been happy with it ever since.