stereo5,
I have a SL1200G that Ralph modded for me with a Triplanar tonearm. I too use the Oracle Hard Acrylic mat that Ralph suggested. To answer your question; I have used the Oracle mat without removing the sticky back. My mat is not, stuck down to the brass platter. IMO, sticking the Oracle Mat to the brass platter is not necessary.
Ralph,might disagree with me, just to get every last bit of SQ that this might allow. I do not think it necessary.
I tried, the stock rubber mat, a new felt mat from my LP12, An old cork mat, an X- treme carbon fiber mat and some type of firm gel mat The Oracle mat provides great sonics through the entire spectrum. Highs are clear and extended without being harsh, Mids are right on. Bass with my Lyra is tight, textured and more solid.
I placed a small piece of blue tape on the edge of the mat and on the brass platter and marked them to detect any movement / slippage. Nothing has moved since I placed the mat in June 2017.
I also tried the brass record weight from my Kuzma TT, A SOTA reflex clamp, a Stillpoints LP1 record weight and finally settled on a 315 gr HRS record weight.
The Oracle mat and HRS record weight work well for me.
If you decide to stick the Oracle mat to the brass platter; you will need to drill 3 holes in it to access the 3 bolts holding the brass platter if you need to, in the future. It would be hard to remove the Oracle Mat without damage if you stick it to the brass platter.