ABOUT / SPECS
I would also comment that something like a Garmin G5 would take up very little room and replaces the traditional six-pack at a very reasonable price point. For total redundancy, you can opt for the Wing Bug which would provide the traditional six pack and full AHRS with recording capability independent of the electrical system of the Aventura II. Since this aircraft is not certified for IFR flight these two options with ForeFlight should provide a large margin of safety as you fly traditional stick & rudder.
I'm a fan of glass... in experimental world, can run apps that replicate traditional steam gauges if that's what you want, and can also run AHRS, moving maps, tailored engine gauges, etc. This airplane is awesome for VFR seat-of-your-pants flying, but... if you're cross country, flying through complicated airspace, IFR, etc, glass gives you more options to tailor your crosscheck.
Big and basic traditional instrumentation. This is a fun airplane to fly, looking inside should be kept to a minimum.