[SOLVED] Fractional font size setting overridden

[Guest]

I used to edit the file ~/.kde/share/config/kdeglobals and set the smallestReadableFont size manually to have a fractional component, such as 7.5 or 8.5, because the KDE font dialogue does not allow setting sizes with fractional parts. Now, after a change in all font sizes through the System Settings panel, if I set the smallestReadableFont size manually, it gets overridden by the size that was selected in the System Settings panel. If I log out and then log back in, the file contains the size that was selected in System Settings. I tried removing the write permission from the file after setting the size there manually, but to no avail. I am using Plasma 5.6.5 through the Kubuntu Backports PPA on Kubuntu 16.04 (Xenial). Is there a way to set this font size manually and have the system use it instead of the size selected in System Settings?

[Guest]

The following is a crude workaround:-
1. Use the Adjust All Fonts... button to set the font with the fractional part.
2. Using the Choose... button change all the fonts other than the required ones (e.g., Small) to whatever size is needed.
3. Apply the changes, log out and then log back in.