The bridge assembly in question is a cheap and cheerful Ebay 5 string bridge which works surprisingly well. It does have floating saddles so I could experiment with putting something under those just to see. It would be a bodge, but that is my speciality There is no way of loading aftermarket saddles onto it sadly:( They are not Gotoh shaped.
I figured that the pressure of under bridge plate or neck pocket would be too much, but it is good to actually have that confirmed. Thanks