Hi Mark - am I too late?!
I'd go for supersoft, because I think bigger balls are better (fnarr fnarr) so you want to be able to squish them down.
I'm a bit of a fad-buyer, so I have 2" oranges having seen the David Stone routine - I use these most - and recently bought some 3" greens having been working with Spongeball Toolbox
My 3 tips (other than going for supersoft) would be:
1) Start with 2" balls. It'll feel slightly more daunting to start with but then 1.5", 1" etc will be a total breeze. If you start with small balls (yawn...), any time you want to move up you'll be feeling slightly pushed. I mean, you'd cope, but why not start high?!
2) I don't like red because I worry people will instantly think of something they got in a magic trick set. I would always go for a slightly offbeat but bright colour - green, orange, yellow - and think of some interesting patter or at least an amusing line to do with the colour (I'm going along the line of bogies for the big green ones...!)
3)
To anyone who has that Eugene Burger video: When I got the big green ones, even though they were supersoft, I wanted them as soft as possible, so I put them in hot soapy water. I instantly regretted it - the colour started to run (and before you turn your nose up at the quality, yes, they were Goshmans). It's not terrible, but they are slightly faded looking now, as if I've used them for a couple of months.If you do feel the need to soak your balls (oh, grow up...),
cover them in hot soapy water, then let it go cold before you ring them out, more of the dye will stay in. Because mine were big, the tops were poking out of the water, and there's a subtle patch of paler sponge on each one because the dye didn't "re-set" on that bit.
Oh, and...
4) Breath a good couple of lungfuls of air through each ball before you perform if you can, then even the super softies will pop up lovely like.