The spirit level listed on the equipment sheet has an accuracy of 0.5mm/m. Over 16.3km, this is +/- 8.2m, which is around the size of the expected curvature drop of the globe model. This means that while the spirit levels can help aim the lights, they should not be considered measurement instruments. If they are, they should by demonstrated to read level "both ways" on a level surface as part of the experiment.
Some people can tell time by the sun, but I could never make out the numbers.
Has a digital level been considered ? Furthermore, is "level" that important for the experiment? If it were critical, I would go for the more advanced technology, unless your overall goal is to show how easy the experiment is to reproduce without advanced technology. (Except lasers)
Cheers and I look forward to the event. I hope this propels humanity further along our journey and discovery of real truth.
A spirit level is totally incapable of producing an absolutely level line of 180°. Every degree has 60 minutes and 60 seconds with in it, a spirit level could not produce any indication of what degree it is sitting at based on an air bubble in glass tube. Simply primitive, unreliable and non repeatable.
A transit must be used to produce a level line of 180°.