Joachim is a tall guy that serves big with a small flexible racquet. He definitely would use the Prestige and RD Mids (If it's a Yonex, it must be a paintjobbed RDX500!). However, he is not a Pro Staff 85 or 90 guy.
There'll always be a what, a where, a when, a why... Synapse is the how!
vCore Tour 89; Luxilon ALU Pwr (ice blue) @63 lbs., on a full string plane