Nitroman
Addicted to ArboristSite
I'd definitely work things out on the flow bench before I looked for gains on the dyno. Unfortunately, I don't even know of anyone who has access to either, so I thought I'd give a practical answer.
There will be a lot of variability between cuts just due to the wood itself before you even factor in human error, but like everything else, you deal with the variability by doing replicates and quantifying the error before you make a comparison.
Build'em. I have two sets of plans for the flowbench, but believe the dyno would work better overall. I had been thinking of a smoke machine to watch the flow on the bench, but that would be messy after awhile. Still.......