It's peripheral on both intake and exhaust, I think.
It looks crazy, but Nitromethane requires very "rich" air-fuel ratios, from memory. Having looked it up, 1.7:1 still sounds crazy. That's mostly because it contains oxygen, increasing the energy that can be extracted from a given displacement of air - so long as you can pump enough fuel in, and then burn it. Alcohols are similar, only to a lesser extent.
Rotaries have very strong tuning phenomena due to the rapid area increase when a port is opened, as compared with normal poppet valves (desmodromic actuation is used because it can generally be a little more violent). This makes them more sensitive to the acoustic tuning and port timing aspects, similar to a two-stroke. So at certain engine speeds, it'll perform beautifully, but at others it will basically be misfiring all the time and dumping raw fuel out the exhaust. That's over and above the combustion chamber shortcomings affecting low speed running.