On a budget, I'd go with regular old SU HS6 carbs. Properly rebuilt and with the right needles, they work really well. Most of the Z-T rebuild price is cosmetic; you can get a perfectly good functional set for a lot less.

I don't personally think there's any real advantage to HI-Fs. With the HS6, you don't need to invent a throttle or choke linkage.

SUs have several performance advantages over the DGV, even a trick DGV:

1) They're bigger. HS6 has 44mm throttles, multiply that by two. DGV has one 32mm and one 36mm throttle.
2) All manifold runners for the SU are the same length -- this does have an effect on tuning. DGV has two long and two short runners; you tune for the average and no one cyl gets set up for max performance.
3) SU manifold gives a straight shot at the intake valve, with very little turbulence. DGV manifold requires the mixture to go around a bunch of turns, which knocks som portion of the atomized fuel out of the air.
4) They're simple -- buy two correct needles and your done spending on tuning. DGV has two idle jets, two main jets, and emulsion tubes and air correctors that don't come in the IPD jetting kit. You may or may not get lucky on those.

Don't think I don't like the DGV, even having said all that. It just isn't as well suited for performance applications as side-draft carbs, which seems to be what you're after.

(Phil now ducks the volley of cannonballs from people who think the DGV performs better than SUs because they replaced nasty worn out SUs with a shiny new DGV...)