The H110+ although nice because it supports 13 slots and runs out of the box without any major settings from BIOS... HOWEVER  the cons are - slots very close to each other so you need to pack them and be careful not to get them into contact with each other. The board also need 2 x 4-pin molex or SATA power onto the board.

The TB250 12 slots however is better designed, dont need the powered molex onboard. BIOS settings a bit tricky but once set up - runs stable.

I have 6 of the TB250 running RX470s quite nicely - fully populated. I have 3 x of the H110 too - running stable also with RX470s.

I didnt get the 19 slotter because this kind of rig poses many different challenges like PSU, power consumption, circuit allocation and cage design.

Anyways, I think focusing on the riserless mobos is better strategy moving forward. Save money on unreliable risers, better heat control and lessen OS compatibility issues.