As a long time fan and user of the Funk Firm Achromat on both my decks I have been satisfied with its benefits over other mats/combinations.
Preferring its presentation to direct on my acrylic platter on my modded P2 and using it with an SRM Tech 2mm silicone mat as underlay on my SL-1200.
I always use either a Michell clamp or a Bruil pattern weight with this mat, both to increase drive/reduce possible slippage and to ensure best contact of the record with the mat to enhance its dissipation of the excess energies generated within the record by interaction with the stylus (which is what it is designed to do).
I recently came upon the idea of improving the bonding of the mat to the platter by interfacing the two with a thin layer of either silicon grease or petroleum jelly (recommended on another forum in connection with the SL-1200 in particular and relating to the now available specially recessed Achromat for the SL-1200).
Not having that mat, I decided nonetheless to try the technique on my acrylic platter.
I carefully applied a thin coating of vaseline to the bottom of the mat, spreading it as evenly as possible with an old credit card, then placed the mat on the platter (which I temporarily removed from the deck) and slowly rotated the mat on the platter applying pressure to spread the vaseline and remove air from the interface (akin to making a "rubbed joint" in cabinetmaking).
After cleaning the small amount of squeeze-out and replacing the platter/mat on the deck, I naturally played several records.
To me, the good effects of the Achromat seemed enhanced, not startlingly, but appreciably, with surface noise being less obtrusive and somewhat softened, soundstaging somewhat better and previously difficult to follow vocals, such as Rickie Lee Jones on the "Pirates" album, being more distinct. Instrumental timbre on the Sargent/LSO recording of Pictures at an Exhibition also seemed enhanced with individual instruments showing more of their particular character.
Seems worth a try to me if you have the mat and a suitable platter (those from whom I took the idea were using the mat direct onto the Technics metal platter).
I'm on holiday at the moment so I haven't been able to try it yet. Has anybody tried anything like this?