Helderberg,

First I think your question is only about reduction of pressure on the hands, not about power or saddle to bar drop. They are all interrelated and fitters will worry about finding the optimum relationship between saddle to bar drop given your saddle setback, but I don't think you're asking that. At least it's not easy to be clear about it in a small number of words. And I'm not the one to try to attack it for you.

For that simplified problem, Berner's example is correct, same for AnthonyG's test. I saw it in a book by Lennard Zinn and I tried it - I think it makes perfect sense. If you pretend you are a ski racer and bend forward with your knees bent into a tuck, your center of gravity needs to be over your feet. Otherwise you will fall over, forward or backward. The skier accomplishes this by letting the butt move backwards. Since the only thing supporting the weight is the skier's feet, the skier has no weight on his hands. For a cyclist, the feet are each on a pedal, so the cyclist with zero hand pressure would have all weight centered over the BB. This would also dictate necessary saddle position, regardless of frame geometry. You have the challenge to position the saddle so it holds your sitbones. The solution could require moving the saddle, replacing the saddle, replacing the seatpost, or even replacing the frame.

In this case you would ride with your hands on the bars however you can reach them, and the maximum amount of weight on your butt, i.e. saddle. If you can position the saddle so the widest part is under your sitbones (fore/aft adjustment) and there is no pressure on the tender bits located forward of the sitbones. This can be very comfortable, in my experience. My legs can generate power in this case, by grabbing the handlebars and pulling up, say when climbing.

If you had your bars at "optimum" height before this position change (I can't, and won't try, to tell you what "optimum" is), you will probably want to lower them and possibly to move them back, but I can't say for sure. I know that I can feel where the best position as I acclimate to the new butt position, after adjusting the saddle height for good leg extension when seated. You might need a narrower saddle if this change has you folding your torso down more deeply. If you didn't have your bars adjusted well before the position change, the old handlebar position could be a better match or it could be a worse match.

Power? As I get used to these position changes and re-optimize my position, I get more power by riding in my new, more comfortable position and where necessary making use of standing and of pulling up on the bars. It usually fatigues my glutes, which means I am training them to produce more force. I don't race or measure myself by other riders - my goal is to ride longer with improved comfort. Comfort makes it easier to use the power I have.

I hope this helps!