Just to give some more data points on this, we were there on Memorial Day last week. Checked in to Breakers around 10:30am and they gave us a room immediately! So that was awesome. Probably entered the park around 11:30 and as soon as I realized everything was running, went straight to a gift shop to buy FL+ with the Platinum discount.
Anyway, SV seemed to be 90-120 every time we saw it. I guess we got lucky because (though I didn't time it), I feel like we never waited more than 10-15 minutes. For reference, the FL+ line was around the bottom of the stairs. Granted, we did walk by once and it reached that first turn as mentioned above. Also, they were running 3 trains and it double stacked every time. They seemed to not care about zipper pockets. Everything had to be out. At the same time, it's not like they actually checked your pockets. The next day, SV seemed to open around noon.