Hi Daryl,
i can't claim to be an expert, but i may be able to interject a couple thoughts....
you described the boring/slotting tool arrangement, your analogy is correct- the longer the boring bar, the higher the tool lift on the return stroke.
if you look at Rudy K's boring bar, it's length was short.
the shorter the bar, the shorter the lift would be on the return stroke- the converse is also true
the clapper box only claps if it needs to, if there is little rearward pressure on the tool the tool will skate on the work
if the cuts are deeper, the tool may receive more resistance from the work as it is traveling rearward and subsequently the lift would be higher
as with any cut, rigidity will dictate depth of cut.
custom boring bars can be made to give the tool some clearance as well, to limit the tool lift for long internal cuts.
the cutter angle being more acute rather than perpendicular.
i think the most important part may be, the boring bar being of sufficient size to make the cut, but not interfere with the work.