Its 50% Bonus: Leve w/Rest give 320 per node hit, when rest wears they give 210.

Its not a flat rate, its a percent. I had 50% of my bar filled at L49, so 50k, but when I swapped to my 39 job I also had 50% of the bar filled, or 35k. If it was flat rate then my L39 jobs bar should have been filled 75%, which is was not. This means it benifits higher level jobs more than lower level jobs.

I am not sure on accumulation rate but I assume its .5%-1% per hour, maybe 20% over 24 hours which would be the GA rate.

And leve rewards don't count towards it, they will "push" the bar. If your bar is red it may seem like it is, but your bar just gets pushed further in the next level.