I have a list of the blocks I used that really work well and use MOST of the senders fabrics...they are all from Quilter's cache. Only one did not come out right no matter what I did...so I won't use that one again!
I do believe that some blocks should be outlawed...like a snowball, and a 9 patch...and there should be a set amount of the fabric sent used in the block, like about 1/2 of the F8th.
you can use the legal envelopes to send the blocks back just beware that they will cost you $.88 to send back or more if you wrap them in plastic and they weigh more than 1oz.
this is a great fun swap, but for first timers, there needs to be a Recommendations list to help show the patterns that work best, and a list of TO DO things before the fabrics arrive. Like pull some blenders out and wash them. If you have to buy some pick some normal colors like green, blue, yellow, brown and 1/3 yd does several blocks!
As for posting when fabrics arrive, I think if each person just posted an arrival UPDATE each Sunday evening that would be enough...trying to wade through 120+ pages to find INFO is hard when your time at home/on the PC is so limited!
I do like the idea of a piece of paper stitched to the edge with the name of the block and the senders ID name. That way you could just post a group pix of blocks each Sunday on UPDATE day and there would not be so many pages to go through to see the pix.