Hi there Mister, long time no see!
Curtains has two way of editing the titlebar buttons
1 - Using the Buttons section: this method is more limited and will mostly change the basics of how the Windows buttons look.
2 - Using the Advanced Section: Here you need to edit the code by hand but you can change the position and experiment with some of the WB code.
Please notice that there is separated sections for the buttons background and glyphs, but you can use 1 other them or booth, depending of the design you have in mind. Using glyph only will limite the buttons size because of an Windows limitation.