I used ZMT with both EKWB and Koolance Compression fittings (10/16). The ZMT ID is tight, but workable. Wet it first before slipping it on.
The EKWB fittings were tight but could be tightened down by hand.
However, the Koolance fittings (on my Koolance disconnects) I had to put two wrenches on to tighten it down to stop micro-leaks.
Build: Z390 ACE
Core i9-9900K OC 5 GHz, MSI Z390 ACE Mobo, AMD Radeon VII GPU OC 2K MHz
Corsair Vengeance RGB 32GB 3200 RAM, Phanteks Enthoo Pro M SE.
EKWB Z390 ACE Monoblock, Bykski Radeon VII GPU w/b, 2x EKWB 140 Revo D5 Pump & Res.
Aquacomputer Aquaero 6 LT USB Fan-Controller, Quadro, Vision Touch and 'High Flow' Sensor.
(2x) HWL Black Ice Nemesis 280 GTS XFLOW and (1x) Alphacool XT45 X-Flow 280 radiators.