If you think that you have
those horrible carburettor things
, it's time to overhaul the carb!
Some thoughts for you...
CHT = Cylinder Head Temperature [indicator] is meaningless for leaning. EGT = Exhaust Gas Temperature [ndicator] much more useful. As Big Pistons says, the fuel distribution will be rather uneven between the cylinders on carb'd engines. I do, however, recommend a four cylinder scanner EGT because it allows you to see which cylinder is hotter or colder in real time. My experience (more than 2500 hours using a scanner on carb'd engines) is that often the fuel distritibution will change with power setting. You may find a power setting in a useful range, where the mixture distribution is even enough that good leaning really works well for you. One place where EGT is wonderful, is the occasion of sticking open an exhaust valve. When this happens, you'll know which one right away, and that will save expensive diagnosis, and removal of he wrong cylinders.
As for fuel flow, yes, they will work with carbs, but not as well as fuel injection. As carbs have a float bowl, and metering valve, the flow on the back side of that valve, is not necessarily representative of the instantanious fuel flow in the engine. I certainly would not attempt to lean a carb'd engine with a fuel flow indicator, other than over a rather long "trend" period. For fuel systems with no fuel pump, the fuel flow systems make me nervous, as they have very small flow holes in the transducer, and it wold take little to block them, with no pump presure to keep the flow going. We had one in a test C150 once, but I would not do it again.
Generations of pilots have managed very well with carbs for more than half a century. Yes, fuel injection offers some real benefits, but carbs still work, and will often continue to work in conditions where fuel injection becomes unreliable, as long as the carb is operated properly. This, particularly, in the context of a fuel pump or flow problem. With your wits, you can nurse a carb'd engine home more easily than an injected one after a problem has become apparent.
I hope this helps...