Well, the title font size is probably too huge to fit on these decorations. If you need to make the fonts bigger than the decoration, you are going to have to pick another decoration. Either that or edit the decoration, probably involving some image resizing with gimp or whatever.
The height of the title bar is controlled by a line similar to this:
+ TitleStyle Height xx
Being 'xx' the height in pixels. You will have one of these for each decoration probably. You should be able to see them by using
grep -r 'TitleStyle' *
inside ~/.fvwm/ like in the other example above. Changing the number in this line you will make the titlebar bigger, however the pixmaps might not fit correctly (I am not sure, I rarely use pixmaps on my windows at all).
About the other elements: each fvwm component can be customized separately. For the menus, you should be able to change the font adding just another line to the function above, so it would look something like:
+ I DestroyFunc StartFunction
+ I DestroyFunc InitFunction
+ I DestroyFunc RestartFunction
+ I DestroyFunc SessionInitFunction
+ I DestroyFunc SessionRestartFunction
+ I AddToFunc StartFunction
+ I + I FuncFvwmLoadAllHooks
+ I + I Test (Init) Schedule 10000 Exec exec conky -o -y 0 -d
+ I + I Style * Font "Shadow=1 SE:xft:Sans:pixelsize=21:Bold:minspace=true"
+ I + I MenuStyle * Font "xft:DejaVu Sans:size=8:encoding=iso10646-1"
Of course, use whatever font you want instead of that one I posted.
About the panels, that would require further analysis. The module that is used to pain the panels is FvwmButtons, it's usually invoked using something like:
Module FvwmButtons MyPanel
And configured using something like:
DestroyModuleConfig MyPanel: *
*MyPanel: Colums 10
*MyPanel: Rows 5
*MyPanel: Font "xft:......."
"MyPanel" can be whatever string, it can even be "FvwmButtons", no problem. So you will have to identify the name of the panel first, looking for FvwmButtons in your config, once you know the name of the module, you will need to search for a line starting with "*name: Font.....", and change the font there. I can't really be more concrete on this one.
However, as someone said above, I really advice to build your own. It's gonna be easier in the long term, and it will give you a better understanding about fvwm.