Bruce,
I've never heard the Reference 8. Is it a smaller monitor like the Tablette 50 Signature? I've always wondered if the Ref 8 sounded closer to the Tab 50 than the 1SC.
As far as sonic characteristics go, I think it comes down to a matter of taste and system synergy. I own both the 1SCs and Tab 50 Sigs and enjoy them both but for different reasons.
The Tab 50 Sig is like a young, gifted, exuberant twenty year old. Whereas the 1SC is that same person but at thirty years of age. Settled, refined and more confident. The Tab 50 Sig is quicker and more energetic than the 1SC and I might favor it if matched with electronics that have a darker character. The 1SC on the other hand I find to be more composed when rendering complex passages and less unsettled by higher volumes. In my listening room they have done better with systems that were a bit forward.
If the Ref 8 is ported like the 1SC and Tab 50, care should be taken with placement as far as proximity to the rear wall. The midbass can get hooty and boomy. I've experienced the same side effect with certain amps that accentuated those same frequencies. The BAT VK200 I'm using now solves all those issues.
I periodically use a sub with both monitors, but have found that it isn't always necessary. Since getting the BAT, I've found that the amp powering the ProAcs has great influence on the quality of the bass and ease of integration between monitors and sub.
I'm sure your Super Tablettes share the same sonic attributes ProAcs are known for...big, expansive soundstage, beautiful midrange and pin point imaging. I notice Reference 8s coming up for sale occasionally. Why not take a chance? Good luck.
Dean