I have the habit of reading different forums concerning the bikes I have. As always, you can't believe everything on the net. But some people seems to have very long experience. Some thoughts of them:
Measuring flow on new jets sometimes shows up to 10% difference.
The parts in a Monobloc that wears is the throttle slide and bore. Also needle and needle jet. On a worn carb, increased throttle air leak can be compensated by higher flow through needle jet. Replacing needle and needle jet can make it run weak.
Fuel level in float chamber can change replacing float, check.
Not certain if it applies to Monoblocs, but a new float don't always move free, check if it needs trimming.
Personally have bad experience with a new Matchbox float chamber from AMAL. Even after adjusting, it didn't supply enough for long straights, racing the Manx.