Hi katrina gardener,
Cuttings taken above the "Y" will always be shorter and probably bushier. To get a true "replica" of the parent plant, the cutting must be taken from below the Y. It's really personal preference. I've never grown one cut above the Y, but I'm thinking I want to try one cause it takes so long for the others to bloom..

I always take cuttings down near the ground for taller plants. The suckers are good for this too. It will obviously take longer before they bloom. For example, I took 2 sucker cuttings off an insignis pink last year. This year they are 5 ft. tall and one just put out nice blooms and the other still hasn't bloomed but looks very green and healthy- it is still getting taller... In a cooler climate it may take even longer to bloom.
I put these type of cuttings in smaller pots this seems to force them to grow taller instead of bushier. I pot up as they grow. Be sure not to give these 'tree cuttings' bloom booster until they are the height you want them to be, or they could 'Y' off and give blooms. I just use regular fertilizer or tomato fert. and epsom salts until I am ready to get blooms. If they do start to grow any branches down off the stem or suckers just cut them off.
~SJN

I agree with all of the above. I prefer the tall tree form so I plant my brugs way low in the pot (or the ground) to encourage suckers. Then cut off the old growth & root it for a friend. Then keep the sucker from underground well fed & watered to gain the height you want. I'm up north & usually have to give up flowers for the season if I want to do this, but next summer - look out! They'll be gorgeous.