PowerPoint: print slides - enlarge their size
As you said, the slides on standard handout prints have a lot of blank spaces between them. In order to print the handouts without spaces and just with black lines between slides, you need to head for the Printer Preferences and find out if your printer has an option to print 2x2, 2x3 or 3x3 pages per page. We have a Xerox printer at the company, and it lets us print multiple Powerpoint slides in one page without spaces between them by this way.