I would shoot the things you want in slomo in 60 p in adobe you can interpret footage at 24 fps and you have a real slomo more than half the speed. In daylight you lose a stop or of light which isn't bad at al.
I shot recently 50 fps in cinema tools batch conformed it to 25 fps and edited in fcp7 looks great.

Blacmagic resolve also free can export to everything. But you need the right graphics card.

You can opt for an offline workflow. Place your rushes on an external drive doesn't have to be fast. Create proxy files in by example in davincy resolve.
Edit those in fcp (This works with fcp7 doesn't know of fcpx).
When finished editing make xml relink to original hq files copy or consolidate to internal drive ta make use of your sad. So you only take with you the used files. and then apply collor correction and fx.
I hope this makes sense.