I went through thew same round of questions a few months ago. From my personal experience, I've gotten REALLY hot domestic water, but I don't think I would anywhere near the amount of hot water needed by baseboard.
(actually, I sort of tried.) I got the boiler water temp up to ~150F with the stove and turn on the circulator pump. The water was below 100F in less than 10 minutes./
p.s. I have the SAME problem you have. RR, stove in lower part of the house. We have 2 bedrooms and I cut a vent into each bedroom. The I ran insulated 8" flexible duct from the top of the Magnum Stoker to a 6" tee then off to each bedroom. It helped a LOT!!!
The bedrooms are as far away as I can get from the stairs (which I'm using for a cold air return). Greg pointed out to me that it's one thing to get the heat into the room, but without a place for the cold air to return downstairs, you are not going to get the results you hoped for.
Here's a post about my hot water hookup.Harman Magnum Stok- Hot Water Coil Update - It's HOT HOT HOT
In the 1st post you'll see a link to my original post. Beware. I asked a LOT of simple questions as this was my first experience with heating systems.