I have good success metering flake powders such as 700-X or Unique but I use what I consider a better quality powder measure.
For handgun, I used an RCBS Little Dandy for many years but as my load requirements changes, I moved to a Redding 10-X. The fixed rotors of the Little Dandy were just not flexible enough for my needs. The Redding 10-X is designed for pistol level powder charges. When setting up the powder measure, I throw 15-20 powder charges to settle the powder column in the reservoir before attempting to measure the powder charge.
The flake powders require a bit more time and test charges to get them to throw consistent powder charges. But even so, the variability of the charges are a bit more than with ball powders. But, in the end result, the variability does not seem to matter. The ammunition is suitably accurate with the flake powder powder charges.
I'll agree that using powders such as W231, Accurate #5, or True Blue are easier to set up, but with a little bit of work, the old school flake powders can provide excellent results.