Anything above 750N on the lower tension side is fine. Just make sure there are no individual spokes with lower tension.
You can’t do much about it anyway. You pretty much have to take what you get when the drive side is at the specified 1200N and the wheel is dished and trued. If you have individual spokes with tension on the low side you can try to even it out with neighboring spokes, compromise trueness slightly or go above the 1200N limit slightly. Spoke tension drops noticeably once the tyre is inflated, so if you take that into account you can go a bit above the 1200N.
You can improve things when it comes to component selection. Asymmetric rims help. Thinner (1.5mm diameter middle section) and therefore more elastic spokes on the lower tension side can be a good idea because they are less likely to loosen.
If you know the spoke angles you should theoretically be able to calculate the ratio of the forces between both sides which is necessary to keep the rim centered.