In my experience, there are two distinct groups of Echinomastus in cultivation. The first group includes intertextus, dasyacanthus, laui, unguispinus, durangensis, mariposensis and warnockii. These are all from fairly standard Chihuahuan Desert habitats and can be treated much like any other Chihuahuan cactus, with drenching waterings in late spring through the end of summer and a cold, dry winter.
The other group is erectocentrus, acunensis, johnsonii, arizonicus. These are adapted to biseasonal rains of the Sonoran and Mojave deserts. Periodically soaking, cold, damp conditions in winter with suddenly warmer days and complete drying. Periodic thunderstorms in very hot conditions in summer. Usually pretty much bone dry fall and spring. Additionally, these plants are fairly narrowly adapted to highly mineral, low organic soil and live completely exposed, in full sun, in very quick drying situations.
The best results I have gotten with the second group is to plant in clay in mineral mix, water with rain or acidified water and observe the precipitation cycle of their natural habitat. Not sure how important winter water is, but I do know that any significant amount of H2O in spring or fall is highly risky. By comparison, although "touchy," the Chihuahuan group is much easier. All Echinomastus do well with as much fresh air as possible, no peat and a quick drying mix. Elevate the bases of the plants above the soil. Don't use any top dressing.
For a sense of the biseasonal rain patterns for the second group, go to weather.com, navigate to the "averages" display and check out a few locales such as Benson, AZ., Wickenburg AZ, Death Valley, CA., Bouse, AZ., Meadview, AZ. etc.