As far as I know, there is only this standard size. The adapter consists of 3 parts, the two screwed ends and the middle part (approx. 43cm). The minimum distance between the handlebar head and the seat post is then approx. 43 + 2x 5cm, i.e. approx. 53 cm. A 'normal' ladies' bike needs about 55 cm, a men's MTB quickly reaches 65 cm. These are 'my' measurements. I hope this helps you. Theoretically, you could 'build' a new centre section (shorter hollow bar with 2 threads).

I can't answer that. I'm sorry.