87/100 with no refreshes spent today.
I'm going to wait for evening bonus Fleet energy, see where I'm at, then titrate the final refreshes based on that.
I did a total of 4x 200 crystal refreshes over the event at different times when I thought I was too close to losing the pace. (My goal was to stay 10 blueprints ahead of finishing pace so that if I hit the final day and had bad RNG I could still hope to finish).
It's likely that I'll need 8-10 shards to come from refreshes. With an average drop of 3.6 blueprints per refresh, that means that I could have passed on 2-3 of the refreshes and saved 400-600 crystals up front, with spending more on refreshes today at a cheaper rate. At worst we're talking 400 crystals saved, and with the problems that are inherent to RNG, I'm happy with my decision to trade those 400 crystals for peace of mind.
I mean, it's not likely, but it's still possible I could rack up a bunch of zeros. Better ahead of the game on a few wasted crystals, if the RNG allows you to get there.