Solid platforms or speaker stands for JBL L65s?

My JBL L65s (c. 1978) were originally sold as floorstanders.  The tweeter, however, has such narrow vertical dispersion that raising them off the floor is pretty much universally recommended. (An oft mentioned height is 12-20”.)  While I would definitely like to get the tweeter closer to ear level, I like the bass characteristics inherent with the speakers directly on the floor.  My question is - Do you think I would retain an appreciable amount of this room boundary, bass factor by raising the L65s with concrete pads or some other solid platform structure as opposed to, say, a Harbeth style stand?  Tilting these speakers backward is sometimes mentioned but, for me, that would ruin this particular speaker’s visual appeal.  Thanks.
You should find wood risers on eBay, complete with JBL logos. I can’t say if the JBL logo is from the factory, but I think they look cool in any case. They were very reasonably priced when I saw them.

I used to have L100s.  I found a stand with some tilt mandatory.  At less than 12" rise, I did not feel the bass suffered (actually probably an improvement to reduce the room interaction).  I don't know about your room, but placing speakers on a riser with a much larger area than your L65 base could act as a room boundary.  I have seen this before with L100s on a long fireplace outer hearth.  Just thinking...
Music Direct sells stands for the JBL L100 speakers that should work perfectly with the L65.  They tilt the speaker back at an angle to disperse the highs.  The stands are made by JBL. 
Well,...I relented and tilted them back, lol.

Seems like that’s the common thread in most discussion I’ve been reading over the past couple of years and, as it turns out,  with good reason.  All I had to do in my environment was to slip a 14” length of 1x2” under the fronts of the built in risers on my L65s with the thickness rather than the width of the 1x2” providing the added height.

Substantial improvement!