If I may ask; what's your experience doing this with smaller models like gpt-5.x mini/luna on the lowest reasoning setting? Does it work well?

I've been thinking of doing the same since the models will often take design decisions that I am not a fan of, or make changes in a way that is easily understood by me, which leads to tech debt and being unable to anticipate what it will take to deliver a certain feature (e.g. whether we should build on top or build from a clean slate, etc.)