Is there any reason why these systems would cause problems?
It should work just fine. Try both taps and see which one you prefer, my guess would be the 4ohm taps, but try both.
I bought a Rogue Atlas Magnum II. Will my gear will match well with it?
I got a great deal on a big tube power amp. This is not usually my cup of tea, but for the price, I couldn't pass it up. I would like to roll it through both of my systems and get an idea of what tube power will do. Is there any reason why these systems would cause problems?
1st system: Denafrips Hades preamplifer (solid-state, line stage pre) and Monitor Audio Gold 100 5G speakers (4 ohm, 86db. These need some power to really shine.)
2nd system: Luxman L-509x (will use the pre-out) and Harbeth Super HL5+ speakers (6 ohm, 86db. Easy to drive.).
I am curious about the 4/8 ohm taps with both set ups and whether or not the preamps will be a good match, technically.
I had a Cronus Mag II driving Harbeth SHL5+ and the pairing was spectacular. the Atlas should be great and give your Lux amp a run for the money. should also work well (but not as well) with the monitor audio speakers depending on room size and distance to speakers.
the rogue is an excellent sounding amp and a great value.