Does it work for you? If it works it is enough, if it doesnt work probably not enough. I have never tested that low.1V SA and 1,2V VDDQ TX is good for working settings and both on 1,2V too worse for lower subtimings for still 3600?
It is going to vary from MB to MB and IMC to IMC, memory sr vs dr, hynic vs samsung, timings etc. Too many variables. I think it is probably too low but you need to test it for yourself.
To me it makes sense to start higher and lower so you know it is not voltages as the limiting factor if trying setting that wont boot or trying to get stable in Windows.
It is a balancing act too high doesnt work and too low wont work.