This will be extremely interesting WPTE.
I am sure alot of users will look forward for your results.
I have some experience in long distance links in .b and .a and i can tell you not only power is important in a quality link, but mostly SNR , and most cards tend to kill quality of signal when is pushed to limits (raising power).
In this matter some word have drivers too.
But what i mean with this is real help is not a wifi analyser, but a troughpout determination with all encryptions and modes/power will help more because here we have short distance and powers beyond 80-100mw will do nothing good, only choke rf preamplifiers.
The best thing to do allways is put best antenna you can get.
I will try shortly with a dublusectorial 5dB from some PROXIM pci clients, wich have a professional manufacturing and is only 10 cm long .
You now, the 80 mw is alot of power for this aplication, keep in mind the wifi cards on laptops is 15-30 mw mostly, and you will see your ap from far but not or bad connection because the minipci cant keep up and push this amount of power.
So, the best for us is the best throughput we can get with quality drivers and settings, and of course antenas.
I can detaliate more of this if you want (real construction, diferrences and performances of different antenas), but remember the "antena" in router and laptops is a piece of wire about 2 cm long ....the bad concept you can get but costs is almost 0 of thise ... shame for all who product this.
I can put here some pictures to see a real 5 dB sectorial .b/.a from proxim, and to understand how we fight with paper swords.
Y crack alot of thise sticks who is callit antena, and allways i find the 2 cm wire inside, no matter how long and thick look from outside, grrr.