Alot of weight on the hands usually indicates too much bar drop. Also, with the saddle nose tilted down like that also adds more weight on the hands - plus you mentioned that you feel like you're sliding the down on the saddle. This will add more weight on the hands as you're pushing yourself back up on the saddle. For startes, I would level out the saddle - nose to rear, and also raise the stem 10mm or so, or flip it so that it is raised.