Would you consider buying this horse for your breeding program? If s/he needs that much assistance in attaining a gait - is this horse truly 'naturally' gaited? Not only that, but if you look carefully, these feet are quite long (which also adds weight)...then you add the shoes, and the boots...and in about 5 years (probably a lot less time) you'll have a horse that has torn all of his tendons and is no longer sound. But man...you had a 'balanced' gait for a while there didn't you?
If you are considering purchasing any horse that needs this much help to gait...back away slowly. If you are considering purchasing a horse that needs you to cantle sit in order to gait...back away slowly. If you are considering purchasing a horse that needs you to yard on the reins with say...25 lbs of pressure constantly...back away slowly.
A gaited horse should be easy to ride, and easy to keep in gait as long has s/he has been brought along carefully and with some consideration to conditioning and appropriate training. DO NOT have your horse trained by a 'traditional' 'certified' Icelandic trainer. Any local trainer can train your horse, just don't have them mess around with gaits...babies simply can't be expected to maintain a gait for very long. That comes with time.
If you can imagine...the woman depicted in the colour photo was actually teaching a clinic on 'cantle sitting'. I hope her students didn't pay a lot for this advice. I wonder how many horses went home with sore kidneys that day?
This is where a LOIN is. Stay off it.