Thanks, everyone for the comments and please keep them coming.
Yes, I had heard curved lines should be used for the quilting but hadn't yet found a design that I liked and could do well. I've even tried drawing designs on that Glad Press and Seal stuff - I think that is what it is called. Have you tried that? It works pretty well.
To answer Mindless's questions, I'm using a Sulky 40 weight variegated quilting thread that is blue and yellow called Butter and Sky, I think. I will test to be sure, but I think I'm using a dark blue Bottom Line 60 weight thread in the bobbin; the back is solid dark blue. I welcome any comments. If that doesn't work, my next thing to try will be a smoke Monofilament Polyester. What is your favorite brand? I have a Bernina that should handle that well.
I want the stitching to be noticed, but as an element in the quilt, not as the primary point of interest. In other words, I want the fabrics, blues and yellows, to be the stars of the show. I want to put as little time in it as I can in order to make it nice, and as much time as it takes. I should deliver it in two or three weeks, if that gives you a better idea. I've tried large loops and also curves with loops, stars, flowers, or hearts, and I did like that look. It's also quick, as you mentioned. I would prefer to do a QAYG but will probably not be able to do that since the back is 108 " wide and four yards long and I don't want to cut it. So I plan 6 rows across (14 inch blocks) and 8 rows down, and plan to quilt the center two rows, then the right two after joining them and then the left two. I may add borders later. I guess it is a very modified QAYG! LOL
Tying really isn't an option. People at my church have seen many of the quilts I've made for homeless families and the quilting on them and expect to see some nice quilting now. Funny thing is that on a homeless quilt, I just go right at the quilting and it always comes out fine and now, with this quilt which will get such scrutiny, I'm cautious. It will be displayed on the wall of the community room for about a month while tickets are being sold. I want it to look good, as good as possible. Did you ever feel that way?
I thought about Baptist fans but it seems to me it would be very labor and time intensive and require a good deal of precision. The same thing applies to the orange peel design. Am I right about that? What is your experience with those designs?
I will try the 1/4 stitching on each side of the seam on my test quilt. Thank you for that suggestion.
One look I had considered, and tried out on QAYG log cabin blocks, is a SITD with a decorative stitch, such as a feather stitch. I liked the look of it with the variegated thread. It's fun to do one block at a time but will take a huge amount of time for a quilt that big. I used a Pfaff for that. With the built in walking foot, it's up to that challenge.
Another look I considered, and have tried on a medium size scrappy log cabin, is a stitch where I free motion quilt curves about an inch long, waving from one side of each seam to the other. That looks good and is quick and easy. It also have the advantage of reinforcing the seams, which never hurts even though my seams are all intact and uniform. I wish I had a machine that did a nice Serpentine stitch, but I don't.
I welcome all ideas, suggestions, and comments. Thanks!