Indesign and changing a spot colour to CMYK

Back once again...

OK, I've just come back to this thing I'm doing and realised that the above dimensions aren't actually A4. What I've done is set the trim size as the document size (instead of A4 297mm x 210mm), the bleed 3mm around this and then the type as a margin within the trim/document size. So that's 12.5mm margins on top and bottom and 9mm left and right. Does this sound about right?

Fanks!

Ladies and Gentlemen...I am back to bother y'all.

I've got spec that says:
Type size - 255mm (d) x 198mm (w)
Trim size - 280mm (d) x 216mm (w)
Bleed size - 288mm (d) x 222mm (w)

Now...I get what bleed and trim is. What the funk is type size?

Thankin' ya!

Mike.