I barely felt the difference going from 7.5 to 7.75, i think i wouldn't be able to tell the difference without a measuring tape now.
The last few months i've mostly skated an 8.25, but i set up an 8in chocolate deck recently with venture lows and some 44mm boardycakes, and I swear it feels exactly like the 7.75s I was on.
If you ever get the chance I strongly suggest giving Magenta's 7.75 a go, really nice shape and good wood.