What exactly are your calcium problems. Bone issues? Low blood calcium? Did you have this diagnosed by an endocrinologist through a urinary calcium excretion?
What exactly are you meaning by the BA calciums being too big -- they are chewables, no? Are you chewing them? I'm not sure how one chokes on a chewable, so if you can describe the exact problem, that would certainly be helpful. There are many other things to try, so do not fret. There are capsules, tablets, small sized tablets, liquids, etc.
There are many other vitamins and minerals that support bone health if that is your issue. This is including, but not limited to: magnesium, vitamin D, vitamin K, boron, even certain B vitamins have been implicated. Plus, too much of certain vitamins are detrimental to bones as well (like Vitamin A). I will need to know more about your supplement schedule and lab values.
Also, if you are on a certain set dose of vitamin D, and you are still deficient, I do believe the obvious solution is to increase the supplement--do you agree? I have seen many DSers take 50-100, or even 150,000 iu of vitamin D daily.
I realize that it is a lot of work, but in order to get to the root of your problem, it would be very helpful if you would share any and all laboratory values that you have in an excel-like spreadsheet (you can upload to GoogleDocs, click share, and provide the link), along with the normal ranges that your lab provides.
This plus your daily dosing schedule and anything else you have already tried will be incredibly helpful.