I'll assume that your bridge curve is properly matched to the fingerboard curve, as I'd expect from Upton. It looks quite normal to me.
What you're asking about can be done, limited to the point where the bow starts to strike or rub the body. However, increasing that curve enough to substantially change the relationships between strings requires changing both the bridge and the fingerboard, and taking that much off the fingerboard is a one-way commitment of expensive wood. So you'll want to consider carefully before you leap in.
I bow a five-string with less bridge curvature than this. It requires good control of the bow, but isn't really all that difficult for me, and I'm no great shakes with a bow. Are you sure what you're experiencing is due to the setup of the bass, and not your own bow control? Do you use a tight or loose bow? Are you putting enough arm weight into it to depress the string under the bow?
=> "I can’t seem to really get the bow on the side of the string"
I'm not clear on what you're going for here. The string doesn't care which tangent the bow follows, as far as I know. Can you clarify?