I would advise you to go with the WLE650V5-25 if you want to have the best TX power per radio chain. It is a perfect card for countries with a EIRP of 100mW ( 20dBm ).
Say that you set an output power of 17 dBm and that you use 2 antennas (x2 the power so +3 dB) with 2 dB lost due to the antenna patchs and 3 dB lost due to the diplexers used by the Omnia and that the antennas for the omnia have a passive gain of 5 dB:
17+3-3-2+5 … 20 dBm
Furthermore, notebooks with 3 radio chains are not common and I do not think I ever met one with 4. So you migth as well spare you the trouble with the power hogs that are those 4*4 cards.
According to my experience, you will not met any problem with the Turris PCIe version 1.0 x1 interface of the mPCIe slot. But it is true that an official answer is long overdue.