Font issues in rich edit control

I'm trying to make small, superscript characters in a rich edit control, but I'm having problems. I cannot get the font small enough. Basically I can put any value for yHeight, but it doesn't do anything unless the value is quite large, in which case it makes the font huge. Here is my code:

Code:

CHARFORMAT cfFormat;

cfFormat.dwMask=CFM_OFFSET|CFM_SIZE;
cfFormat.cbSize=sizeof(CHARFORMAT);
cfFormat.yOffset=100;
cfFormat.yHeight=1;
	
SendMessage(hwnd,EM_SETCHARFORMAT,(WPARAM)SCF_SELECTION,(LPARAM)&cfFormat);

Are there any problems with that code?

I googled for "superscript rich edit" and found some interesting comments at this site:
http://www.codeguru.com/Cpp/controls.../?thread=30510

Perhaps the font you're using is incapable of rendering that small....

gg

I've used a couple different fonts, so it might not be the font. That site you directed me seemed to deal with what proportions one should use, not how to fix my problem. Thanks anyway.

One other thing I've found, if I retrieve the font size using EM_GETCHARFORMAT, it is the same value, 257, no matter what I've set the font to. This happens even when the font is set to something like 700, which actually makes it really big.

EDIT: Actually, when using EM_GETCHARFORMAT, no useful information is returned. What is going here?