I understood that… I think. I assumed you meant 2 x 30° horns per 3000 AP but I guess maybe what I didn’t understand is you are wanting to just connect a single horn to a 3000 ? I don’t know how/if SU works on the 3000 or if it’s only MU… but in theory 2 2xMiMo antennas pointing in the exact same direction should give you a meaningful improvement in RSSI / SNR and thus MCS rates which translates to more capacity (the better the MCS rates of all the clients the more clients it can handle)
I’ve tried to sort out exactly what you lose if you only connect 1 2xMiMo to a 3000 and… not really much reliable info and I have never found the free time to experiment. We had almost 30 3000L’s at one point and now I have none because they never failed to find a way to cause me grief. Terrible radios IMHO. The 3000 on the other hand is a great radio and I wish Cambium had supported it better with more antenna options.