Finally got it to the water today. Looks like the port side is leaking around the steering arm, but the starboard side doesn't seem to be coming from exactly the same place. Now that I've been able to study the transom assembly in more detail I guess the inside and outside pieces don't mate tightly together so there's enough of a gap for things to leak from the top down.
It still looks like my shaft bellows' are ok and that the water is probably leaking around them as it drains down. I took a couple pics so we'll see how they come out.

I had a slow trickle from the steering arm area o few years back......if I remember correctly, there is a grease fitting for that joint. I greased mine and the leak stopped! Worth a try.