those sensing pumps suck, the johnson pumps are pretty good, their float switches suck. I like having a separate outlet for each pump, that way I can tell if they work, My emergency pump outlet is mounted directly over the main pump outlet, if I look back and see two streams of water coming out at the same time, I know I've got something going on in the bilge(alarms fail). I've seen bilge hoses break(especially that white corrugated hose), if one hose breaks, you will have both pumps pumping back into the bilge

absolutely run each pump to it's own thru hull...... once you get over the "I skeered to drill a hole" issue you will realize that it is actually simpler and that with two thru hulls you will actually have redundancy... IE a busted thru hull taking out both bilge pumps would be BAD and adding two check valves that reduce gph (and could fail) and SEVEN more hose clamped connections to possibly fail is anything but simplicity.

just drill the hole... you will be FAR better off in the long run

I am adding the thur hulls and i also added switches to the 2 new auto pumps today, this way they can be off when boat is in the yard, just leave on when in the boat or on the mooring