'ability to trim the board' probably describes the major advantage to strapless norm. Glad u gave it a try
In choppy conditions u'll find that strapped will be less comfy,because ur front foot needs to be further forward. This lets the board hold more volume,and cushion the chop.
Strapless lets u compensate for choppy conditions, wrong kite position, water currents in light wind and tweak things out
First pointers id say about jibing would be to do a kinda stop start transition,where with slow/medium board speed slowly take the kite to 12 while bearing down wind. Just as the kite hits 12 (board not toeside), push the back of the board out to spoil board speed, redirect kite quickly and at the same time do ur fancy dance moves and smile for the camera.
Intermediate jibes technique and airs tutorial will come at a later date. In the mean time, jibe jibe jibe jibe and jibe!
One thing to remember is every board is different,and wants different foot position for different conditions of water and wind. Play with different foot positions,move ur center of gravity around on the board and try different boards once u can jibe,say, 8/10 times on one specific board. I say this because by then u'll be able to feel the difference in boards,and further improve ur technique as every single board offers a new technique to add to ur style.
Dave