Gut feels or speculations are difficult to apply. As I said before, you need to measure your own system. Most PD users are reluctant to do that. If you're running a gen then it's a worthwhile exercise.
As I mentioned, if you're only interested in a 2 hour charge then you can raise the absorption voltage on the Iota to 14.3V. The PD doesn't climb to 14.3V until 90 minutes into the charge. If it was designed correctly it would have gotten to 14.4V long before.
What converter do you have? Lets see some measurements.
BTW, the Costco GC2 batteries in my test are not rated 225AH but 208AH. No 30% difference.