Drop the primo altogether. Right now is not a good time to buy primo, too many fakes.(and excellent ones)
The cycle looks great as it is.
For information on how to use clomid, search for clomid FAQ by the iron game.
Arimidex should be used at 0.25mg ED from the first day until the very last day (including clomid). You might still have bloat at 0.25mg, so you can bump it up to 0.5mg ED when on, and then back down to 0.25mg when on clomid.