All my research so far seems to indicate it is not possible to do this accurately. The only two options available to me at the outset were:
a) Using a La
I have a much easier solution, that may or may not work for you.
If you aren't doing anything special with the CATextLayer that you can't do a UILabel, instead make a CALayer and add the layer of the UILabel to the CALayer
UILabel*label = [[UILabel alloc]init];
//Do Stuff to label
CALayer *layer = [CALayer layer];
//Set Size/Position
[layer addSublayer:label.layer];
//Do more stuff to layer