Wotcha matey, good to hear there is another Vitesse build under way
I can confirm that quite a few of us have gone down the route of:
Swing Spring conversion, 1" rear lowering block, stiffer front anti-roll bar, lowered front spring.
And with that set-up on mine i have no issues whatsoever
For all the faff fabricating and locating a rear anti-roll bar would entail, I'd say do all of the std upgrades first and then see how it handles, and i suspect that he'll more more than happy.
Dave