Are there any numbers or numbering on the jets in your carb ?
Once-upon-a-time, all carb jets were calibrated in cc flow per minute.
Not sure when this practice started, or ended, but this meant that a table of standard drill sizes would produce standard flow rates.
Where are you ? In some parts of the world, there are some very experienced carburetor rebuilders, I'm sure that this would be a snack for such a craftsman.
Money well spent, since you don't want to reinvent the wheel, multiple times....
P.S. I'm sure the folks at the new Amal are good, but since they stopped making carbs for some years, all that expertise was lost - or left ?. Some of these newly made carbs seem to suffer some odd reported problems that seem to indicate this - undrilled or unconnected idle passages or float arrangements in particular, which surely means the finished product was not actually ever tried on an engine....