Hi Andy, What I did ... Goto https://www.thingiverse.com/thing:4707289 and download the STL file of this model. Load it into Chitubox and print it at different exposure settings (they only take about 6 mins to print). The pictures below came out of this YouTube video which goes through all of the following. The exposure times marked in black on each were correct for that guy ... you will get different results. What you are looking for is how the points meet in the middle of the infinity shape. These pics aren't real sharp but you can just see that when over exposed the points intersect, when under exposed they don't meet. Correct exposure is when they meet exactly (3.5 secs in the above case - 1.3 secs on my AnyCubic Photon Mono). This worked well for me. I have read also that different resins and different colours can also change the exposure times so I will be printing these if I change resin and/or colours. Good luck ... Chris
Thanks Chris, Look like I'll be doing a bit more testing, I've still to try the Water washable Eco resin, which I really should do before I run out of normal resin. Paul