I like to use the grooved top bars and use a wooden spline in the groove to get them started in the center. Works really well for me. I rip my own wooden splines, but some folks use tongue depressors or popsicle sticks. For me, it has worked better than either the V shaped top bars or the ones with the wedge turned vertical. The main concern is to be sure your hive is level left to right if you put on a whole box of undrawn frames. When using them in supers, they work best when "checkerboarded" between fully drawn and sealed frames of honey. If the adjacent super frames are drawn but not sealed, the bees will often just draw the adjacent frames out wider into the empty space of the foundationless frame.
"The UNKNOWN, huh? That would be SNORBERT ZANGOX over in Waycross."