Yar dude. Boom Boom would be proud. Looks like you're moving pretty fast. You can cut yourself some slack if you're dying by the end - sprints should feel fast but not all out, and the overall load of the workout should be moderate at most.
I'm not pushing all out on the "ons," but the :90 of recovery definitely feels a lot shorter each time. Feels like I'm doing it right. I'm thinking of adding another short set in the middle of the 2 x8 next time. Also, all the "ons" seemed to come on uphill stretches...poor design on your part.
Ha ha - that's why I like speed work on easy terrain. One thing that the Brunswick area is good for, at least.