well there'd be the prop. flow sharing valve for the breaker circuit to supply oil to the
basic tilty control system Ol, plus there'd have to be a prop. valve to piggy back/tandem the orbital to allow it's alternate control, via the sticks and all of its associated pipework ..
from what I've read elsewhere, stick steering's about 1800 quid - a lot of that'd be the cost of a prop. valve to achieve it. Plus any other necessary plumbing to achieve feeds, returns, etc. .... With a 'kit' of bits, organised to fit the gear, before starting, I can well see it being achievable in a day, especially with a van full of 'extras', fittings, hose swaging gear and anything else required by any self respecting, well equipped fitter

..... a day's plumbing spannering could achieve a lot, particularly if it's pre-prepped kit fitting. Wiring also takes time and needs putting in nicely. but when one does it on a daily basis, you'd get good at ..... or go home !!
I'm sure Aiden could contribute a great deal to this discussion, on the 'black art' of tilty installation .... if he chose

If I were to go out and splurge a large wedge of cash on a prop cetop valve, to parallel up with the orbital, it'd be a pretty quick install too, but it'd not stop there .... yon valve'd need controllers and then you'd need a roller in a stick to control them .........etc.

Mine doesn't earn, it's a convenience and a means to an end.