As far as I have seen, in a gasser, the ring tension just starts the process. Its the combustion pressure that actually pushes the rings out and down. Side clearance (the dimension from the top of the compression ring to the top of the ring grove) allows the pressure to reach the critical area. Problem is that is an obvious issue, large side clearance can cause its own issues on high rpm or motors that need more endurance. Gas ports drilled straight down from the top of the piston to just behind the ring in the groove can provide that pressure to the top and back clearance side of the ring. Then the side clearance can be reduced. This leads to less ring flutter at higher rpm.
Obvious problem with a diesel is the gas ports being clogged quickly. But in a race only application, motor tear down frequency is much higher. So cleaning the ports can be done much more frequently.