In regards to insulin - humalog and humulin-r have different release time-frames so they peak at different points. The person in question (or anyone using this protocol) would not need ~500 grams of carbs during their workout. I do not have this specific bodybuilder's intra and post workout protocol but I can't imagine it would be any different than what most of the pros (and top amateurs) are doing.
I already posted the in depth protocol in a previous thread but heres what I assume it would look like (summarized):
2 hours pre workout - around 100g complex carbs and 50g protein
45 mins pre workout - 50g complex/50g simple carbs and 50g protein
walking in the gym - 75g simple sugars (large gatorate/soda/non-diet energy drink/glucose tabs/etc)
intra workout - 100-200g simple sugars (a common favorite is a large gatorade with additional dextrose powder added), BCAA's, creatine
post workout - 100-200g simple sugars, 100g protein
30 mins later - 100-200g complex and simple carbs, 100g protein
2 hours later - 100g complex carbs, 50g protein