If you use ESKO HD then the resoution will need to be 4000 DPI.
Alternative solution is to used mixed screening (AM+FM) (Like HXM) from harlequin. This can work at all resolutions.
Also ESKO has some solutions that can work at 2540 DPI. (No special hardware required) because this is done using software.
Costs from ESKO are in the range of $10,000 + and from Harlequin in the range of $5,000
but this is one time cost.