I have issues giving advice against Ken, mostly because I’m really not that great. So I hope I don’t spout anything TOO dumb.
EX NDLs are gonna be your best friend (at least they are against the Kens here). If Ken’s turtling and spamming fireballs for some reason, make sure he’s not jumping before you throw one. If he’s bulldogging, anti-air him with 'em.
If Ken is severely jump-in happy (cross-up mk, EX hurricanes, etc.), start getting used to the spacing of that crap and throw out some good HPs. Make him think twice.
Shoryukens…if you knock Ken down and rush him, you’ll see a shoryu (obviously, not being an ass). Few ways. One, the lk dive will stop short of any srk if done right. Two, j.HK early enough and you’ll stop short of Ken’s lp srk. Three, throw out j.HP from as far away as possible…get the Ken player thinking about whether or not they should SRK. The more they think, the more they have a chance to screw up, get hit by the j.HP or, if you don’t do the j.HP, get thrown by you on the ground. (They’re not used to thinking…they’re playing as Ken, remember? )
If Ken doesn’t have any meter left (dunno how often this happens), it might not be too bad of an idea to bulldog him for a brief time. Cross-up j.HKs, IAD - throw setups, something until he gets enough meter for a super…or even just enough for an EX shoryuken.
If he gets close to you, good luck. Keep him the hell away by mixing up close highs and lows (don’t get parried, or it’s shippu). IAD away or IAD and throw him effing asap. If you’re in the corner, good night. Jump and dive the hell out of there or IAD or something, but just don’t stand there.
And, my own stupid thing…I throw out mk every now and again when I’m not anywhere near him and I know he might advance (I do this against everyone). The fact that it moves me forward a little bit throws people off a bit…it might be that they just need to learn that, or it might be that I just like the spacing of it that much. I dunno. Experiment…you’re using Twelve.
…I really don’t know what else to say…sorry. ^^;