Technically speaking, the engine doesn't know if the fuel comes from an injector or from a carby. I could go one step further and state that the way a car manipulates airspeed vs air desnity as it passes through the venturi, it actually 'injects' fuel at that point, using atmospheric pressure.

There's absolutely nothing wrong with drawthrough, and guys have gone exceptionally quickly with it. It's not as easily tunable, but well within a hobbyists grasp, and whilst you can run an intercooler, you can run water injection, and that's enough for you to make some very serious bhp.

You might have seen that a fair few drawthrough inlet manifolds are of the 'log' type - with (for this motor for example) 4 downward runners that curve inward to the ports in the head, and a 'log' across the top connecting them. As 'agricultural' as that sounds, it creates a necessary/desirable amt of turbulence and helps keep fuel suspended and satisfactorily distributed and mixed to produce good power and without danger of leaning out.

as far as designing it goes, keep the path from carby to turbo as short and straight (hopefully not uphill) as possible. from the turbo, out and up to the top of the manifold. It'll be impossible to avoid an uphill stretch there, just avoid unnecessary twists turns and uphill (or otherwise long) stretches. Use a log type inlet, with the log reaching further forward and back than the front and rear runners (don't just round off the ends in other words, and I'll do a drawing if it helps). Other than that, run a decent sized breather on the rocker cover, and run a generous sized return line to the sump. If you don't do those last two things, even a small amount of blowby will pressurise the crankcase and really interfere with the oil draining away from the turbo. if that happens, it can't let the new fresh oil in there (and it acts as coolant more than lubricant believe it or not) and the turbo can fail.

Other than that, run less total timing, as the more boost you need, the less timing you can safely (or beneficially) run. and it'd be a good option to look at some type of electronic ignition conversion, to provide hte strongest spark possible.