I think Shawn is correct here. You really need to come up with something that works good for you.
I've performed testing with many organizations around the world, and each have their own method. And some differ within their own group, engineer to engineer. Some have a very formal layout that's used each time, others just clip the flight plan outline to the panel and use a blank sheet of paper for notes.
It really depends on what data you expect to gather. On aircraft with a complex data system (i.e. RAH-66 Comanche), you really only need to record the run number and any notes to discuss during debriefing. With no recording capabilites onboard, you'll probably be writing like a madman, trying to capture many parameters of data.
On an ultralight, I would think your challenges will be flying & writing at the same time, having enough instrumentation onboard to get meaningful data, dealing with the wind (unless it's an enclosed UL, of course!).
How about a voice recorder of some kind? I've used a system like that before. Wire in your helmet mic to a tape recorder, or even better a handi-cam. Outline the flight plan on a small piece of paper taped to the panel, back of your hand, whatever. Then as you're flying just dictate all parameters you've got to record. Then later watch the tape and transcribe the data.
Good luck.
What to share a little more about your testing???
R. Cal