I have a 12x12 ft gazebo (octagon shaped) to get some sound to.
I will be using an older 50 watt x 2 channel amp for power.

1) If I were to get a dual coil woofer (8 ohms per coil) one coil wired of Right Channel and one coil wired for Left channel and run 2 tweeters will I get a form or stereo from one box?
I was looking at the new Atrium series from Polk....

2) If the woofer is 87.7 dB at 1w/1M will that be the SPL to match thetweeters up to?

3) I was looking at the MCM http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-2185-/55-2185
crossed over at 1500-1800 4th order slope as per Zaph's suggestion for this woofer on his site and mated with 2 appropriatly low fs tweeters possibly the Dayton
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=275-070
The box would be 18 liters tuned to 40-45 hz

Any comments or help would be appreciated.

Or go with plan A posted?