I've wrestled with this question a fair bit, I regularly prepare my own saw cut veneers and having the veneer next to the fence isn't ideal because in last third or so of the cut you've often got this big lump of unsupported timber waving around to the right of the blade.
I tried a third party fence which is geared and accurate to better than a tenth of a mill, the wheel on the end of the supporting rail cranks the fence in or out,
the thinking being the veneer would fall away to the right of the blade and the heavier donor board would be secure against the fence. It kind of worked, but there's one problem. I normally plane or thickness the sawn face of the donor board between cutting each piece of veneer, so at least one veneer face will be a smooth reference or glue surface. The veneers are then run through a drum sander to clean them up and bring them down to final thickness. But adjusting the bandsaw fence a pre-determined distance between cuts meant I couldn't plane between cuts, planing doesn't remove a consistent thickness of material so both faces of the veneer ended up with bandsaw marks. This in turn resulted in many more passes through the drum sander. Given that drum sanders are very slow machines this largely negates the benefit of having a geared fence!
Bottom line, there's no perfect solution, or if there is I haven't found it!