My BCI who is 16 months old and 4,75 feet long digests a large rat and poop it out in about 10 days.
If it takes 1-2 minutes for your snakes to swallow their meals, to me this is an indication that the meal is small.
You said piling food into my BCI, i wouldn,t describe it this way. I would say that i,m not keeping him hungry like in the case of your snakes.
As i said and i will say it again, impossible now to reverse things and give him small rats in order to avoid feeding him multible prey items per feeding. The best thing i could do is to reduce the size a bit and space it up as much as i can.