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.