I have Besta's with Vaasbo glass doors, and the 4 cylindrical extension legs.
- You need some type of legs if you put doors on them. The bottom of the door will scrape against carpet or wood otherwise. The good thing about the adjustable cylindrical legs is you can make the front legs slightly "longer" than the back legs, resulting in a slight tilt backwards. It helps.
- You should secure the unit into the wall, preferably into a wall stud. The problem you mention with bottom molding along the wall is a valid concern. If you screw an anchor directly through the back of your unit, into the wall, you will cause the unit to tip slightly backwards and it won't be flush of course.
However, a little bit of tipping backwards is okay. Also, if you have the lighting taped to the back of the unit, like I do, you need a little space (we are talking millimeters, not centimeters).
Two options - you can get a "brace" that is the same width as your floorboard molding, and secure it to the corner of your Besta and screw it into the wall that way (the little plastic thingy that comes with the Besta doesn't really do this well).
Or, you can get an earthquake strap, like someone mentioned above. These do require you to anchor the strap into a stud, and then secure the strap into the top of the Besta.
I have purchased these, but don't use them because I already screwed my Bestas directly into the wall. But if I had to do it again, I'd use straps... when I change out my lights, I have to unscrew them from the stud and screw them back in... where as if I had the earthquake straps, I'd just unfasten the Besta from the strap, and I never have to mess with my wall again.
I do recommend securing them somehow. Glass doors are heavy. Before I secured my Bestas... if I opened the glass door, the Besta WILL start to fall forward. Using statues as ballast will not work. If you are going to have thousands of dollars of statues, secure them!
Here's a pic where you can see where one of my anchoring screws are: