Teacher's here!
Now listen carefully children; To start with, forget 40-lines - that's crazy! Just use half of them.
Start a 1c/line, then gradually build it up to 4c/line & hit the feature.
Choose 5-spins because I noticed in fun mode that you seem to get a lot more 'random wilds' at this level (the 2 wilds below were NOT Dolphins when it stopped spinning).
Hit a nice one at x15 and Hey Presto!
That's how you do it!
PS: Awesome SJ!