Here is a single up close of one...just I'd share the beauty!

This one is my favorite....just love the yellow

Err, I always pinched the female flowers off before they even opened, as they are single flowered and I didn't want plant to waste energy on them.

Best way to multiply is probably by stem cuttings. Second best would be leaf cuttings.

Third, would be tuber sectioning. And fourth, unless you have a greenhouse would be hard....seeds.

aren't hybrids sterile? you can't grow them from seeds!
if you decide to take tip cuttings, they need to have at least 2 nodes with leaf buds . i read that if you only have nodes where the flowers grew - they won't take.

Curiously enough, tuberhybrida seeds will self or even cross and you can grow plants from them. The only problem is that a full grown plant will show only a tiny tuber at the end of the growing season, so small it will be very hard to carry it over for another season.

woebegonia, it's good to know for the future that they can self-pollinate, i'll make a note.
if i am not mistaken this is a large-leafed tuberous?
if you pinch the top tip and add an inch of fresh soil into the pot too - it'll trigger good basal growth. then you can remove new basal stems when they are 4-5" tall (do not cut, just snap them off at the base) - they would make quite nice new plants. but you'll need to grow them thru the winter with good light. they'll bloom in spring if you have good culture without going into dormancy. or so i read, i have not actually done so myself.
however i did induce the basal growth on my plant- 5 big shoots in addition to 2 canes. and i can see already some buds forming on young shoots too. though mine drops most of the buds - too hot here.
but i want to grow it large to increase the tuber for next year.
new basal shoots will make it very bushy.
you flowers look very nice, i wish mine were better...