That makes a lot of sense.
From my continuing research, the least problematic adapters seem to be those which do not need firmware or kernel modules because they simply have good mainline linux support already.
From the many posts made by @alzhao on this subject, I see that the rt3070 and 8187 are particularly desirable for this reason.
I also understand that these external devices should not have a driver/chipset that interferes with the existing internal atheros chipset present in the Slate - which is apparently the case with the rt3070 and 8187.
Does anyone know if the RTL8188EU in the TP link TL-WN722N V2 from amazon is likely to perform well with the Slate despite the need for kernel module and driver?
Otherwise, as a possible new alternative, I have since found the following website that promesses speedy european delivery (the following link is a relevant blog post by the store):
https://www.siliceo.es/en/the-6-best-antennas-wifi-usb-powerful-for-long-reach/
Specifically: does anyone have any advice on feasibility of using these models with the slate - they all seem to sport the desirable rt3070:
https://tienda.siliceo.es/en/antenna-wifi-usb-powerful/161-wifi-usb-antenna-melon-3000mw-n3000-11dbi-high.html
At this stage, i think that i will either go with the cheapest amazon option (currently the TPlink TL-WN722N V2) or maybe one of these rt3070 devices.
Regarding the rt3070 devices I have my doubts about ability to power from the Slate so I have looked at some specs:
SLATE:
Power Input: 5V/2A
Power Consumption: <6W
From my terribly basic knowledge this means there is 4W of power left to work with. Does this mean that these high gain external devices will work? For instance:
This device is listed at 2000mw power consumption - can I assume that this will run well from the Slate’s USB port alone… I have a sneaky suspicion that it could never be this simple
So I am almost close to an answer:
If someone is able to clear up the power capabilities of the slate in terms of ability of powering one of the high-gain RT3070 external anttena, I will probably go all out and get the biggest badest RT3070 antenna I can find.
Also, if someone can confirm that the TP-link TL-WN722N v2 with RTL8188EU will provide a real noticable improvement in signal levels, functioning well alongside the internal chipsets of the SLate I may just go for this cheap and easy option.
My aim is to pickup wireless signals outside the range of the Slate - ie. worse than -70dbm (seems to be the absolute lowest from my research),
I would like to thank everyone for contributing to these questions, reading all this text and for any further suggestions to help me narrow down the remaining options!!!
Thankyou!