TBCMDButton appears to ignore the size set for Font property.
in the methods TCustomBCMDButton.Paint and TCustomBCMDButton.CalculatePreferredSize
if FTextProportional then
bmp.FontHeight := Round(Height * FTextProportionalRatio)
else
bmp.FontHeight := 0;
should perhaps be
if FTextProportional then
bmp.FontHeight := Round(Height * FTextProportionalRatio)
else
bmp.FontHeight := Font.Height;