Nah you are doing the right thing enigma is the best choice because of teleport. Fort doesn't add much to kick and isn't anywhere near as good of an armor choice imo.
7/3/3/ is the kick speed of dtalon in frames. The first kick in every burst is 7 frames, every follow up kick will be 3 frames. So a 5 burst kick (dtalon level 24-29) will be 7/3/3/3/3, a 3 burst kick (dtalon level 12-17) is 7/3/3 and so on.
The ias bps are different for the first kick than the follow up kicks. For example, with Stormlash (a -10 wsm weapon) you need:
-30 ias to reach 3 frame follow up kicks on fade.
-95 ias to reach 7 frame initial kick on fade.
-50 ias to reach 8 frame initial kick on fade.
So this means with a Shael'd Stormlash you will have 8/3 kicks on fade, but will likely need a BoS setup to reach 7/3 kicks with this weapon because it requires so much ias for that last breakpoint. In the case you use BoS you only need 27+ ias after slvl 3 BoS to reach 7/3 kicks, so you can use the socket for something other than Shael (Jah is best choice for pvm imho) and still reach the max kick speed on BoS.
Everything is explained in that link I posted, along with breakpoint charts.
These are the bps for every weapon speed:
http://e.domaindlx.com/JRichard/D2/aas22/Tables/Kicks/dtalon.html