Drive Base Help

[redfancy]

A bit of background: We had a very very rough season this year with a bot that fell apart multiple times and could barely drive, let alone play the game. In our rookie year two years ago we did very well, but everyone that was on the team that year has since graduated, taking any technical/mechanical experience with them. We have no stable mentorship (working on that, though) and team culture virtually does not exist. Basically, we're a rookie team with no rookie benefits, little commitment, and minimal guidance. So, three of us have decided that we want to get our stuff together and are leading a summer journey to start from scratch and design/build a new bot for offseason, learning tons of stuff along the way. Except, we're very inexperienced (explain like we're five). Plz halp!

Wheel-wise, we want pneumatic wheels for sure. We have 8-inch wheels from our original bot, but because we want to upgrade from a 6WD to an 8WD (moat), we want to switch to 6-inch wheels for frame perimeter reasons. Our major concern is being able to get over drive obstacles-have any teams run into issues with 6-inch wheels on obstacles?

Drive base-wise, here are our ideas:
1. We want the wheels to stick out the front so that drive base height doesn't matter
2. 8-wheel drive
3. two center wheels dropped (also need advice on how much to drop wheels proportional to wheel size)

We have entirely ruled out a custom base and are now choosing between the KoP AM14U3 and VEX's VersaChassis. The VersaChassis looks like it will allow us to fulfill requirements 1 and 2, but we're not positive on whether we can drop the center wheels a significant enough distance to matter on the field. Which chassis would be a better fit for the bot we're trying to make?

Also, got any other miscellaneous tips?

Any and all input is appreciated!