Think of a chest rig or the pouches on your armor carrier as refills for your belt mounted mag pouch. I like to conduct all reloads to the both the rifle and pistol from my belt line. then when I have a moment I will refill the empty belt pouch with a fresh mag off my rig, whether it is just a chest rig or armor, I use both depending on the circumstances, environment, class type..... however most of my chest rigs also have the ability to clip into my plate carriers so that transition is also rather seamless. By always conducting the weapons reloads off of my belt I feel that I am not having to adjust on the fly to finding mags somewhere on my body, they are always on my right hip (left handed shooter)
As for the types of belts, I prefer to direct mount things to my pants belt, I still feel like this is the most secure method for me personally, I also do not tend o hang too much off my belt line if I do it this way. I also have a few Inner/Outer belts of these I like the Eagle industries one the best, I have 2 of these, one set up for USPSA matches and another set up from left to right with a Flashbang pouch (carrying a TQ fully enclosed), holster hanger, LBT low pro IFAK centered in the back, BFG low profile dump pouch single rifle mag and three pistol mag pouches.
For pouches I flip back and forth between the Esstac's and the HSGI taco's, I like the form factor of the Esstac's and I think they are "slightly" faster....for me, but I also have some rifles that are not supported by them so I also use the HSGI's.