I always jump on the bottom level of the first girder, and every girder level thereafter. The second girder level, I do it as late as possible to get points from the thrown barrel, and then on the 3rd girder, to jump over the thrown barrel.
I always jump, always have, always will. I can't mess with my finishing move now, that would be crazy!
On a side note, I posted a thread quite a while ago about how I get pissed when I only get 300 points for smashing a blue barrel. That's total B.S.!! LOL.
I've been playing DK a lot lately, my best score in the last month is 309K.