The cruiser is my favorite. There is plenty of room for a HT. The only problem, for CORRECT instillation will be the need of a modified front mount. There are vendors that sell them. Here are some ideas.
Engine Mounting pictures by Ron-Becker - Photobucket
Here is a cruiser I built.
Mikes HT bike pictures by Ron-Becker - Photobucket
This will be helpful for the coaster, although some cut the dust cap.