The spoke calculator gave me the following results left 292.34 and right 290.98. I am going to buy DT Swiss Competition spokes which are sold by 2mm increments from here. So which spoke length is better to buy ?
Given that there's a bit of forgiveness thanks to the length of the spoke nipples that the spokes will thread into you could safely round down to Left 292mm and Right 290mm for spoke lengths.
An alternative is just rounding to 292mm for both sides - especially if your rim has recessed spoke holes (as most double wall rims do).