I used to ride an 8.38 way back in the day. Had to stop skating for quite some time. When I was able to skate again, I got a 7.75 with a 14 wheelbase. I just jumped up to an 8.25 with a 14.38 wheelbase and like the extra landing space.
Some will tell you wheelbase is the only thing that matters. Honestly, I've found both width and WB matter. Then you get into shapes. Plus you'd be hard pressed to find a 7.75 with a 14.25 wb. I found 7.75 feels like a toothpick in comparison to my 8.25.
Not sure if you're new to skating or not (I didn't bother to read much). But a good idea is to use a friend's board and see how you like the feel of balance front to back (width) and ask yourself "Do I feel safe dropping from a foot or more onto this width?"
Then see how you feel with your feet on top of the bolts. Good idea to also try the front foot near the front bolts and the back foot near the tail. Do you feel cramped, too far apart, or just right?
If you're serious about consistently buying boards that suit you, make notes of any board you try. Measure the length and width of the board. Measure the wheelbase of the deck. The nose and tail. Also, make note of which trucks they are using and measure the WB of the axels.
If you don't keep friends, then you'll have to buy stuff like I did. Sucks, but you always have extra sizes to try different things on.
Wheelbase is a whole different monster that I've only recently gotten into studying, thanks to Ben Degros and our very own SneakySecrets. Different wheelbases of a board paired with different trucks makes a difference. Through hearsay, I've gathered that heavy Indy's feel light on a longer WB because they make your WB shorter. Thunders make your WB longer and feel heavier. Depends on what kind of pop you desire.
If you need any help with how to measure, let me know.
I just wrote all that and it will probably end up not helping.
But, I'm proud of the fact that I didn't cuss once.
Edit: I just read through the thread, you didn't ask for any of this useless information. You better like it anyway.