J.P., I have a question for you about your Retina 5K iMac and the font display.
I'm currently using a 15" laptop, with high native resolution. I've decreased the resolution to help increase my font size, but many of the windows are still too small.
I'm wondering how increasing my screen size (when I get my iMac) will impact the font sizes. Have you previously used a smaller screen? How did switching to your 27" screen impact the font sizes?
My old iMac was set at 1680 x 1050 pixels and the new Retina iMac uses scaling to map to the native 5120 x 2880 pixels, though this is on a 27 inch panel rather than a 20 inch, so even with the same pixel counts, things would appear bigger. The default scaling is 2560 x 1440 (so each "virtual pixel" is mapped to 4 real pixels), and it is to this virtual screen to which applications write. For applications, one can generally adjust the font but certain of the windowing fonts, such as the menu bar, were verging on being too small (even though these small fonts are dramatically clearer because of the enhanced real pixel count). That is why I have switched the scaled size to 2048 x 1152, which results in everything appearing 25 percent bigger than with the default setting.
Now, in RootsMagic under CrossOver, I have increased the DPI within the "Windows" virtual machine from, I think, 136 on the old iMac to about 150 on the new iMac, but the fonts defined in RM have been reduced from a mix of 18 and 16 point to mainly 14 point. The result of all this is that the fields where one can't change the font size in RM appear relatively larger relative to the fonts one can change, which is what everyone would probably want. And I could probably adjust things further - increase the DPI setting and reduce the RM defined font sizes. I'll perhaps try that tomorrow. Note that these adjustments only affect the RM windows - all the normal Mac stuff is affected by the scaling selected (as is RM, in addition to the RM specific adjustments).
To those unfamiliar with the Mac, this all may sound somewhat complicated, but it is really very easy to do. Within System Preferences, go to Display, and change the setting from "Best for Display" to "Scaled" and select one of the 5 choices - the middle one is the same as "Best", I chose the one to the left of it. Within CrossOver, open the "control panel" for the RM bottle (virtual machine) and on the Display tab, change the DPI setting. Then within the RM Program Option Fonts tab, choose whatever fonts work best for you.
I hope this is reasonably clear and helps.