Yes, anything under 8 will open fine and unless you deleted it, 7.5 should still be residing on your HD. I’ve also reverted back to using 7.5 for now. I think any issues I might be having are due to Yosemite as even 7.5 doesn’t operate as smoothly as I remember it did before the OS upgrade (I upgraded to be “more compatible” with 8). The common issue for me between the two releases are mainly graphics hiccups. Because I do a ton of micro VO editing, the deal-breaker is the “cursor/zoom bug”. Not going back to 8 until that’s fixed.