WOW those are some big boy aspherics, I love it!
I have not seen precollimator builds these years. Could you share some pros and cons to using a precollimator?
Does the FL change when you use two lens?
Where do you get your giant aspherics?
If you want to have better assurance on your measurements; I recommend you to purchase one of maukka’s calibrated lights. He measures everything from CRI, tint, to even lux!
Link:https://budgetlightforum.com/t/-/52082
You could get your own lux meter and compare his lux reading with yours to find a multiplier value for your lux meter.