If you don't like heavy switches, I wouldn't suggest going with an SSK. It's quite stiff, ~70g or something I've read? And yes, they feel a lot stiffer than my HHKB.
I'd recommend Ergo Clears. I love my Model M at home, and my HHKB at work, but my girlfriend has an Ergo Clear, and I always love the sound of them typing. They feel great too! Kind of like bubble wrap, and not too far from HHKB, but still a very different experience.