Calculating LT 1 and LT2 approximately without a blood test?

Just adding my 2cents on A1 = 0.75

For me it comes in around SST effort/HR. Have spent quite a bit of time debugging and trying different things. I am just coming back to fitness after a break and 0.75 does equal my old LT1 (if I had to guess).

Will test is once a month and see if it starts to align to what I think LT1 is.