I have not done proper tracking of this, unfortunately, but I'm tempted to do so.
I'm highly confident that I'm way below 50% chance on going first since the change, I'd love to track this properly and get more people involved to generate enough data for this to go from anecdotal to facts based - and either prove or disprove my current feeling.
I do the mirror every time since my success rate is very high, regardless of who goes first, using the reaper method which tend to result in a new series of coinflips (and weirdly, for that second series of coinflips my feeling is much closer to 50/50 on winning them than on the opener).
I will do my best to track from todays climb and hope more will join in.