how do you determine the ideal number of RAC nodes for a system

We are in the process of reviewing changes we want to make for 23c and on question that came up is if we should be revisiting our current RAC provisioning. we commonly provision 2 - 3 larger RAC nodes (usually sized to make sure we can accomodate the largest query/process we would run) but we would like to know if this is a good practice or if we would be better served with more/smaller nodes...