His hair sounds a lot like Rizzo's. Here is a pic of what it looks like when he is a little "grungy" lol.
bath day.jpg
The only time it hangs straight is when I blow dry it, otherwise it'll get curly looking. Even then it only stays straight for the day
Rizzo Cute4.jpg
I say you may as well give it a try during the winter months, just to see how he looks with it. Heck maybe you could just try the "Joey"
It seems to look good on any yorkie
summer cut 3.jpg