Shawn If doing reciprocals, yes, of-course. The principal being that you can most easily then spiral down (allowing the aircraft to drift downwind in the process) before repeating the test in the same slice of air. However, because the time-to-height may be affected by crossing the Isobars (i.e. the relationship between geometric and pressure altitude will be inconstant) I'd only do the test crosswind if I were flying reciprocals in that way (because the mean of the two runs will give a pretty good equivalence to true still air). If not doing reciprocals I'd prefer to plan into or downwind, so as to remove that effect. If doing a typical light aircraft 1000'-5000' or thereabouts climb perf with a limited flying hours budget and a limited test area, I'd probably fly climbing downwind, and performance glides on the reciprocal into wind (in, of-course, good conditions with not too many Isobars and the nearest front on the next continent.)
Sycamore I challenge you to propose that particular technique and use of equipment to any lady member of aircrew, of any level of experience and qualifications, and (should you survive) report back on her response
More seriously, I believe that glider pilots routinely tap the instrument glass with a soft pencil and find that does the job well. But, it's really only turbo-jets and gliders that do suffer routinely from this, and I doubt that our man's Islander might
not have enough vibration at the cockpit to keep the pressure instruments from sticking.
Mentioning data recording, there are two bodies of opinion - some TPs / FTEs record time at fixed heights, some record height at fixed times. It doesn't really matter, other than the data analysis is done slightly differently - but do make sure that whichever approach is taken both the pilot and FTE are expecting to do the same thing. I also often alternate recording IAlt and IRoC, say the first at odd-numbered hundreds of feet, and the second at evens. If there's an inconsistency I usually find it's the VSI that has something wrong with it.
G