As it relates to signup offers/bonuses, you may be better off not requesting a raise. If your prior salary allowed an $X credit line, then your new one may allow $2X. The benefit here is that if you had reached the cap of any bank prior to this, because as far as I know, they do have risk tolerances/limits as it pertains to any single customer in aggregate, this higher salary will enable you to maintain a larger number of credit cards with any given issuer.
You sound knowledgeable and may have already thought through this, so if you really need a higher limit, discuss it with them, but hold off if it isn't really necessary.