Technically, the Orion 2 was much the same beast as the MK I. However, the original idea of using an SME style of base plate no longer seemed appropriate. The Helius version of the base was aligned axially ( down the length of the arm tube ) whereas the normal SME slot was oriented towards the turntable spindle.
Turntable manufactures therefore still had to cut out arm boards for us, and the shape proved awkward. We therefore changed the base plate design to make it easier for them.
Otherwise, the main change was to the arm tube. The original arrangement of clamping the arm tube near the bearings was dropped in preference for having a fixed tube and providing a collar just behind the headshell to facilitate adjust of azimuth. Headshell slots allowing the setting of overhang.
Of the Orion variations, this is the most rare as the collars were borrowed from an aerospace company and we only had a few available.