METR1C you could probably circumvent the restriction and achieve that look by having three different spritefonts:
- Blue with no outline
- White with white outline (8 pixels?)
- Gray with gray outline (16 pixels?)
..And setting them on top of each other (in that order, blue being on top) in the editor. You would possibly have to play around with the character spacing values a bit and it's not a very efficient solution to have three stacked spritefont objects, but should be possible..