White & black's back ranks are both randomised independently. I've played around a bit with evals (a very very small subset of the 921600 starting positions) and white is almost always <= +.5.
Q. What if the RNG choosing a starting position where white is +.9?
A. Either i) Tough. This happens very rarely & it happens randomly hence not biased in favour of one player or another. Or ii) Lichess's server selected the starting position & runs a quick eval, choosing a new starting position if either player's eval is > +.5
Q. Why do you need this? Isn't Chess 960 enough?
A. I don't need it. I would like it. I think it would add strategic problems that aren't available in 960 & would like to try it out.
Q. What if the RNG choosing a starting position where white is +.9?
A. Either i) Tough. This happens very rarely & it happens randomly hence not biased in favour of one player or another. Or ii) Lichess's server selected the starting position & runs a quick eval, choosing a new starting position if either player's eval is > +.5
Q. Why do you need this? Isn't Chess 960 enough?
A. I don't need it. I would like it. I think it would add strategic problems that aren't available in 960 & would like to try it out.