What to do after 145?

I suggest just getting 2:1 ST and demo. Leveling up one of the two means the other one suffers, which isn't as good as leveling both of them at the same time.

Edit: Y U HEK!?

Yes, but if the Skill Updates may come soon to JMS, I won't be really using Demo much even while transformed. The only time I see it being useful is when I go to Zakum/HT, but I still am not able to go there very much. ;x