I'm curious how you figure your combo (or square) bolus. I really don't have much rhyme or rhythm to mine at this point.
I was taught by the local Animas trainer to go 50/50 for high carb/high fat foods, and she commented that maybe some people need 60/40. Oh, and she said to make our I:C ratio stronger for a combo bolus, by about two. (So if my dinner I:C is normally 1:9, she's say change it to 1:7.)
That hasn't worked for me, and I go high. Through trial and error, I've figured out a couple foods that need a combo bolus of like 75/25, but with some foods, that'll make me go low first. I wish I could find some sort of guideline for what to do for different carb/fat ratios. I honestly don't even know how to look at a nutrition label and say, "OK, there's enough fat in this that I probably need a combo bolus." I can generally say whether a food is fatty based on just what it is, but that's hardly precise since things are made differently by different companies/people.
I haven't had a great deal of time to experiment with this yet and probably won't for the next few months (pregnancy doesn't seem like the time to experiment!!!), but I'd love to hear what others do so I have some ideas while I'm figuring it out.