Thanks. Although I now have a center channel that can keep up with the mains without the use of separate outboard amplifcation, the timbre is not an exact match, but it is definitely of unmistakable LS lineage. I assume the woofer compromise to be the primary cause. However, I wonder whether its location (direct center and on the floor), use of newer/different components (AA network vs AL, Atlas PD-5VH vs Eminence's K-55) compared to my L/R, Type LSFBTG 1990 LS's mains have anything to do with it. It might be time to update the components of my mains.
The new center sounds brighter, but no harsher than the mains. I hooked it up on the right channel and played some of my personal reference material and it sounded like a regular LS with cleaner highs and a bit shy in the bass department. Perhaps the cleaner or brighter highs might be direclty attributable to the woofer compromise, plus other differences mentioned above.