Oh wow. I can't believe they made you keep taking it after you threw up the first time. Let alone after so many repeats. Doctors are supposed to know they can use multiple types of prep solution. Mine was called Clenpiq, it was a small 6-8oz bottle I drank half of in one gulp, then again 4 hours later in another gulp. I did almost throw that stuff up, and I'm sure if it was mixed with the electrolyte water like yours was I probably would have.
Why they can't make it tast less awful I have no idea. But mine didn't tast like it was supposed to either, not even close. My last one 10 years ago had me use mirlax and dulcolax. No bad taste, and no inclination of throwing up. Same end result.
And wow 27 megamax diapers? That's way more than I would have guessed could have been needed. Then again you did effectively go through the prep twice in a row. At least you had the supplies and didn't have to result to those medical grade pullups. I don't even want to imagine that.....