What's the difference between both, add simp review both and add trad review both?

I've been skrittering for about a month and a half but simplified only. I'd like to start learning traditional characters but don't want to reset my progress. Can I do this?

Thanks

Yup; just set it to "Both". Later, if you decide to go back to simplified, the traditional items will still be there if you want to go back and forth.

Both gets you both adding and reviewing simplified and traditional.
Add simp, review both: when you get new words added, only the simplified styles will be added, but you'll still review all the traditionals you had from before.
Add trad, review: as above, but reversed.

Thanks Nick.

I have a list of simplified words already in my study list - will skritter automatically pick out the words that are different in traditional script and ignore the ones that are the same in both?

Yah.