Yeah i think a couple of weeks will be fine -- i was told i can add damsels right away. In all my research on this, both at stores and online, i've never heard of waiting two months to stabilize the water -- one month was the longest i had been told. Add with the addition of live sand and live rock, it cuts the time down even more. I'm sure its better to wait longer, but i guess i'm just a silly, impatient [censored].
The Blue Tangs around here only cost about $25 or so and they apparantly have no problem being in a 20 gallon aquarium, as long as there are only 2 or 3 other fish. Once it gets too large, i'll just take it out, sell it back to the store and buy a baby. Some of the tanks in these stores i've been to are as small as 10 gallons. This one place had a beautiful 10 gallon setup with a full reef and about 3 clown fish. Breathtaking.