The voltage regulated outputs have 12A capacity (total) which for most systems is a lot. Honestly you could put them all on the VR (voltage regulated) without issue.
If you must use the high output outlets, which only have 3A more, go by the power rating on the back of the units. Order your devices by maximum power/fuse sizes and put the highest power items on the unregulated outlets.
Worth pointing out that the combined output of your unit is 15A. The maximum output of the regulated outputs (12A) is a subset of the total 15A. You don't get 15A + 12A = 36A, you still only get 15A. :)