Thank you man! Yes, despite what seems obvious, regarding the levels and the - wait scotch... the coils and resistors!!! hahaha , things have been still confusing after the countless discussions.
Richard, I truly think I hit it on the nail with my photo and will eventually post another one on my thread for my own reference. Truly, I think this fuel level confusion needs one simple photo, that's all. In any case, I will stick to my vernier as pictured, I think this is it, at 7.5 mm average as scotch suggests from experience. Most important is uniformity than 1 mm this or that way from what I gather (all three that is, hence the word 'uniformity'). What else would be to it than one correct point of reference and the second where to measure the distance?
Either way, I think I am done with the level subject.. What else can I do?