Rick,
I remember making quite a few jumps with rounds. Rich Stein had the same model as mine that he dyed black in his bath tub. I did a little antenna in LA with it. Phil had that Piglet made of F-111, and it rocked! I would always be low man and would burn that one down and Phil always took pictures. He was into the photography thing.
I saw George Roso jump a Para Commander from a 600 foot cliff over hard land. It was like going back in time, even in 1986.
In certain circumstances I liked the rounds better. They were good when you got open so low that there was no way to hit anything. When Phil and Andy jumped the Astrodome and Superdome, Phil said that they drop tested a square, which opened fast but flew into the stands. The rounds landed in the outfield. That is some funny video.
I guess if rounds were a good idea, they would still be around. Kind of strange how things seem like good ideas until someone shows why they are not. It freaked my rigger out when he figured out I had been jumping my reserve in a BASE rig.
As for size, Phil's definition of a valid BASE jump over water was whatever the world record high dive was. It was about 190 feet or something, and us, not being trained divers, could easily get whacked. I imagine you could make a pretty small one for water. How small, I do not know.
I had a lot of fun with rounds where it was warranted. I have this great picture of John Hoover open way above me with a square and my Preserve about half inflated a hundred feet or so off the water.
Mark