While drop bars do place more weight on your hands and thereby the front wheel, 50/50 is not likely. Even the "new" short top tube long stem (135mm) set ups.

If you placed a pair of bathroom scales under the wheels and got on the bike you would be surprised how little is on the front wheel. With drop bars more like 70/30, a bit more if you are in the "hooks". I have seen 80/20 too, a bathroom scale set up is not perfect but does give you a data set.

Upright bars will place more weight on the rear, depending on the stem length used and where the saddle is positioned, I have seen it moved forward 1cm to happy effect. A wider saddle, or even a sprung one will reduce the shock loading, typically as the back is more upright, the compression loading on the discs increases dramatically, might look at mtb. straight or minimal angle back, say 3 degrees, it will get you higher than hands on the hoods, but could still get your torso leaned forward a bit to avoid compression. Done this for a few guys who no longer had the neck flexibility to use drop bars, and worked well for them. Your mileage may vary....