Hi Ritacarl
Welcome to the board. When I did my TB quilt I used the set in Y seams. I assembled each individual block first then I sewed each of my rows, leaving the 1/4 seam allowance unsewn so I could still do the set in seam when putting my rows together. Sewing the rows together did take a little longer because I had to set in each Y intersection. It did seem daunting at first but once i got going I got into a rhythm and it really wasn't so bad.
Here is a link to a picture of my Tumbling Blocks
http://www.quiltingboard.com/t-22344-1.htm