I'm aware that BT-ing the balance to a lower APR card will not be a good strategy at all. My specific use of low APR card is to use it as a backup if existing lenders won't offer me another 0% and/or highly unlikely emergencies if I ever need to pull cash from CC (I have some cash stored on high yield savings). Pulling cash from CC is a bad idea too. Other than that, I always PIF.
It's possible I read into it a bit more than I could have. That sounds perfect. I would probably still wait though on picking up another one for the time being and work on getting your existing limits up beyond 10K since it's going to take some HP's to get you there unless you opt to diversify some more into Amex, Disco, BOA, Citi, and/or Synch based cards that are SP CLI's.
Landing a low APR card is a bit of a game. If you have lower limits you'll get a lower limit typically unless it's NFCU which hands out 25K lines like candy around here. Pretty much every CU will HP CLI but, some are more generous about auto CLI's and SP's as well. I've found over the years it's about 50/50 on the cards I picked up that they give an anniversary CLI of about 10% of the limit and 1 or 2 of them actually bumped significantly w/o intervention or request to do so. I use them once a year to keep them alive at this point since my focus changed from CU's to bonus hunting w/ the big banks and collecting their free money.
My 6.9% is stuck at 16.5K because I no longer "bank" with them and their policy for stand alone CC's is to cap them at 5K. There's little nuances like active banking products that influence them beyond the initial opening of the share account and CC app. To get better results during the app it's kind of a gamble on how they'll calculate the CL but, most of them base it on a DTI calculation and they're not typically a high CL even over time. Most of the cards cap out at the 25K range, there are some specific ones that go up to 100K but, it's not worth the trouble to get to that point on a mediocre rewards card.
A good resource for these types of cards is Galahad15 If you go dig through some of his posts you'll find some hidden gems he's stumbled across over the years. If it's out there he's probably gotten it or applied for it.