It's fixed!
Since I used the FEL as a jack and lots of big blocks of wood under the tractor, the hardest part was putting back the rocker pin in the steering mechanism connecting the new spindle axel to the tie rod, just an extra trip back home for more tools and an extra hour.
Drew thanks! Your link helped a lot. You had the right part number in your link to "All States". "Yesterday's Tractor" listed only one spindle for the 3610, the one I had to send back, but when I told them I found the spindle on another web site they asked for the part number and said they had the part listed for a 2310 but if I'm sure by the measurement that that is the right part they would give me a break (only $7) on the shipping charge (since I had to return the other spindle on my dime ($35), and they also had the part for $14.60 less.