Wall mounted turntable shelf - how stable?

I am considering a HIFI Racks Podium turntable shelf to

solve a positioning problem I have. I understand that the shelf

itself is quite good, but does anyone have such a shelf fixed to a

plasterboard wall (at best a wooden upright behind the p/board)?

Is the considered wisdom that only brick is stable enough?

My speakers will be close to the same piece of wall (no sub in use

for stereo music). At present the TT is on a table next to the RH speaker.

Any advice welcome.