Disclaimer: This is from my experience, so if someone say's I'm wrong...um, I'm wrong.

First of all, STSF does work a lot better for elves and dark elves. Arial's are possible, but realize that charges rack up based on your int vs. their int. So an arial will have a harder time getting charges faster compared to an elf. This also means that fighting elves of basically any sort will for the most part negate the STSF. I remember gaining charges pretty slowly, or not at all, against arials and w-elves as an elf so keep that in mind. If you fight stupid races a lot, STSF is plausible. (Also, remember that STSF is a "better in the long run" sort of legacy unless you're fighting giants. So if most of your fights end decently quickly, I wouldn't advise this. I don't knwo if you're caballed, but if you aren't this isn't as great of a legacy in my mind since people don't really have an obligation to engage you after several fights unlike in cabal raids and such where they know you have an advantage after several fights but they still have to come and fight you again.)

Dance upon the S.W. is also from what I've seen from a char I had that had it and from what others have told me, doesn't work as well for already dexy races. A giant who has it will find it more useful than an arial. This isn't to say it won't give you a boost, but probably not an enormous amount.

Whirlwind is nice with mace/dagger because of all the massive -dex, which will be useful for you. Also, daggers are one of the easiest weapons to parry. Maces, not so much as a decent amount of classes don't know how to use it (i.e. most rangers, assassins, most mages) but the main purpose of whirlwind (at least from what I've seen), is the -dex part and not the parrying part. Combine whirlwind adv of dex + concealeds that fire off of your wielded dagger and you should pack a punch.