Can I use a twin needle on my Janome Sewist 725s? If so, which one?

New to sewing and this is my first machine. I've read the manual and their general website instructions about using a double needle with their machine. But it doesnt specify the model. So I'm confused about which needle number i should be looking at, and whether this model will even take one?

I'm trying to hem some long men's T-shirts to fit my 5'1 short torso needs. My practice runs on scraps have just been with a zig zag and a straight stitch. I could make it work i think, but hemming tutorials with twin needles just look so.. polished!

TIA!