Third members question

There are fine spline and course spline yokes, so you'll have to use a yoke that not only fits the spines of your new ring & pinion, but also the driveshaft u-joint. The yokes will interchange between housings.

You could swap the old yoke into the new center section if the splines and u-joint size match. But whoever is setting up the new gears will need both centers to set it up. However, keeping the whole old 3.23 center as a spare could come in handy if you ever need the gearing for a long trip.