Love that movement, Bug!
I've forgotten the measurements on my round and it isn't out for the day yet -- today I will be putting on the border. Spent the last couple days with the hubby he had a half day Saturday and Sunday completely off, today he's back on 12 hour shifts.
I think with my round on it will be somewhere in the 52" square realm and that it currently measures around 40". The pictures I show are on a queen sized bed, so it is still a couple inches short of the width on either side, but not a full round -- or maybe one side of a round would show fully.
I personally like bed sized projects so size isn't so much an issue for me, and I started with an 18" square. I'm still really comfortable with people doing what they feel needs to be done and/or what they want to do on my top. I think for my group it will be too late to turn the projects on point after this round. As I did the math for my original idea, it was about 8" wider (total, or just 4" per side about equivalent to a 10" border) on point than with a finished 6" border, and I felt that could be accommodated easily by later rounds turning it rectangular. Size was always a concern, and after this it starts getting really big with that diagonal measurement. Maybe still could be done but maybe in partnership with the person after you, each doing half.
If it's time to turn mine into a rectangle, that's fine with me, you can do top/bottom or just a wide side or narrow or whatever! I've envisioned me doing a final round with the Basket Blocks from Mary's Stash (not our group Mary but made from the stash of fabrics I used) and that it will end up rectangular at some point/some how because I prefer them to square tops. If you want to tilt my top, or off-set it in some way, feel free and try to have some fun along the way.