Here is the Technomadia review of the MIMO unit that I bought, the one that was later discontinued for reasons nobody understands. It shows photographs of the set-up. This was a rare case where Technomadia actually published content that they normally keep behind their paywall. I had a full membership with them for about a year, and they went into greater depth of description behind their wall, but basically they extolled the virtues of this thing all the way around.
I have a three antenna-like devices: the weBoost with its thumb-sized OEM "stubby", the MIMO that mates directly to the Netgear air card for which it was designed, and a high-gain shark's fin that I can connect to the weBoost instead of the stubby. Last summer when I was off-grid for an extended period, I experimented with all three. All produced different results but none could get me a reliable 4G or LTE signal. The weBoost working alone with its stubby antenna did better than it did with the directional shark's fin, which also makes no sense on its face, but an unusually large number of variables were involved here. I was in a sparsely-populated area of Canada where the cellular system is patched together with Kleenex and spit (PM me if you would like a link to an op-ed I published in the regional newspaper regarding it). The Netgear air card clearly revealed as much (it logs a great deal of technical information and I have a bunch of screenshots showing what signal it was pulling at any given moment). weBoost plus stubby could at least get me something akin to a weak 3G part of the time.
I didn't have an ideal mast for the shark's fin, and that was part of the problem, I think. I've been looking for a good telescoping mast for which my husband can weld a receiver onto
the custom hitch carrier we made, but I haven't found one yet. Those things get really expensive really fast, as they are used in professional broadcasting and military contexts.