Wow, thanks so much to all of you who've provided such detailed assistance!!!
Maureen NJ: the chart on Bonnie Hunter's website is great!! (It's not that I can't do the math, I was just hoping not to have to!)
tessagin: Yes, I know how ridiculous I am as far as the 'waste' part goes, especially considering the size of the blocks (see below) that I'm doing (I almost edited my earlier reply to you to say so ;p).
Fastpedal: I know nothing about EQ7 other than I think it's quilt design software? I did draw out my intended result on graph paper (at least six months ago!)..[ATTACH=CONFIG]572648[/ATTACH] I've been reading a lot about quilting since then, and have done a railfence top since then that taught me a lot - via mistakes I made). I've caught up on other things that had deadlines, so I plan to actually start cutting next week!
Sheila Newhouse: Yes, the putting together part was also a concern. Does it seem reasonable to do the individual squares (9 patch and snowballs) first! And worry about the oversize snowballs later?? I am concerned how they'll 'fit in', but I expect I'll check in here when I get close to that stage.
Fastpedal: yes, the putting together was a concern. I plan to do the 'easy' ones first, and then check back here when I get closer to needing to fit the oversized.
bearisgray: Yes, I think it's the 'floating look' that particularly appeals to me, and the oversized snowballs were where I had less confidence in my drafting skills.
Again, thanks to all who replied - your assistance is much appreciated!