Need help with an under quilt.

[SeekSolitude]

I decided to take the plunge and try a hammock on my BWCA trip next month. I've been mulling over the multitude of options and finally decided on the Eldorado (thanks Shug). But now UGQ, Loco Libre, EE, and HG are backed up so far that I won't get it in time for my trip on May 14th. My top quilt is a UGQ 850 fill and was planning on getting a similar quality under quilt. My UGQ topQ is a 20 degree, but I am sure that I can easily get by with a good, comfort rated 30 or 40 degree under quilt. Any suggestions for a quality alternative would be appreciated.

I have to decide on a tarp as well, but I think I have some options there.