As a reference, when I changed my oil the other week and also finally installed the new iron 'high-flow' oil pump from John Phelan, I collected and measured about 54ml /~2oz from the timing chest.
Last change I measured what came from the sump straight after stopping, about 150ml/ 6oz.
As the pump is higher flow I assume that is feed flow, but I see a stronger return at the tank too, so I'm wondering if the amount in the sump will change too; I guess I'll check that next time.
I think the only way to reduce the volume of oil in the timing chest would be to park the bike on side stand with the rear wheel up a ramp or similar, to allow some of the oil to flow through the only aperture to the sump, this aperture being under the pinion. I thought to make a drain-through, but doubt it be possible.
On a different note; Musky I think I debated in a different thread that my sump pickup is on the right-front(or left-rear?), it is in fact right-rear
Quick edit; Since that photo, I've wired the pump screws but that photo would've been too busy