They ran various pitot tube setups like a line of pitot tubes either side of the role hoop extending 1m either side and also on the floor especially in the undercut region (before + after the tightest sections of the undercut channel), and some pitot tubes in the sidepod inlet but yeah no proper aero rakes like other teams all used. Perez did say on Thursday in media that the pitot tubes weren't giving reliable readings, so that's perhaps why they're doing so much flow-vis.
I've never seen as much flow-vis as they're using - they almost never send car out without it