I already TAG protein. Don't seem to need to for fat. Unfortunately the type of bolus I really need isn't supported by the pod -- basically, a 3-part bolus: Spike, flat extended, spike. I can only do spike followed by flat. So I spike the carbs, and square bolus the protein over 3 hours.
That produces the best possible results I can get, short of having to bookmark in my head to do another bolus about 2.5-3.5 hours later to catch the protein spike. I just don't have the patience to add one more thing to remember and act on for this disease.
All that said, I speculate that insulin resistance makes TAG'ing harder to maybe even impossible with the current pharmacodynamics of fast-acting insulins. I find that carbs act very fast -- true to the literature, they seem to be fully digested and peaking within about an hour. The proportional insulin taken to cover the sugar takes pretty much the full 3.5 hours of action to get it back down.
In other words, there just doesn't seem to be any way to directly counter carbs mg/dl for mg/dl because of the timing issue. All I have been able to do to really "handle" carbs well is play the pre-bolus timing game, drive my BG down to 70-80 before I start eating, then eat. I still get a significant rise, but it's relative... a 50pt rise starting at 80 is 130, rather than 160 having started at 110.
I eat a burger for lunch with 40g carb (and nothing else) and no matter how I manage insulin dosing I'm going to see 50-60 mg/dl rise. The only way I can avoid this is to eat NO CARBS.
As Dana Carvey as George Bush I would say, "Naht gunna dew it"!