Ron
Yes, I am relying on the consistency of the insert to maintain centre; I'm still on the first of ten ISCAR brand items and feel these should be within a thou or so. The initial adjustment was, of course, set by facing the under side of the turret. In principle, I think the same approach could be adopted for a conventional HSS blade set level with zero top rake.
In the GHT post I have on the Myford, however, the slot is angled at 7 degrees and the projection is then varied to set the height.
In either case, as you say, the idea is that the tool is retained by the shallow dovetail, (8 degrees in the GHT turret).
Congratulations, BTW, on your cross slide and good luck with the RTP!