There's no known way to get rid of the sandstorm in BW2. So you'll have to treat it like NPCs, brining up the menu asap as you're doing. It's annoying, but doable.
Although you seemed to already figure this out, the sandstorm does advance the frames before you even gain control (i.e. during the season screen/immediately after) so you'll have to find your SSF.
Yeah, figures. This is gonna get dumb. =X
You see, could it be that the game still advances frames the moment you get the menu up (since you see the sandstorm raging) or does it advance frames when you leave the menu? The moment I try using Chatot calls, I get really weird frames.
I did some tests with a new Seed (target 325) and got the following results:
With 0 advances:
Calm, Somewhat vain,
311 or
319 (twice!)
Bashful, Capable of taking hits, 151, 199, 205 or
315
Bashful, Misschievous, 100, 216 or
335 (a bit slow on purpose)
Jolly, Somewhat vain, 158, 175, 186, 237,
307 or 457
Naive, Misschievous, 93,
323 or 463 (thrice, by going 'slowly'!)
Modest, Capable of taking hits, 150,
359, 442 (I believe I was a bit slow here)
Docile, Misschievous, 142,
363 (slow here as well, I think I used the menu)
With 6 advances (assuming I hit 319 regulary):
Mild, Alert to sounds, 476
Lax, Capable of taking hits, 157 or
349
I think it's fair to say that my range is somewhere between 307 and 319, which is a big range. The thing is, I'm fearing that opening and closing the menu does not work in my favor at all and I'm afraid I'll have to just hope I time it right. I think I'll do a couple more tests without a Syncher to see if I can somehow hit my frame or at least close...
Also sorry for all the dumb questions, BW2 RNG is a little more annoying than I initially thought. =X
Edit: thank god I send over my Master Ball for easy checking though. This would have been a horror without. XD