Here's a strat that's (mostly) budget and a way to 3-turn the node used to farm Great Knight Medals. I say mostly because it requires two copies of The Imaginary Element. If your Arash has a level 10 battery skill, it only requires one. Everything else is low-rarity or free.
If your golden sumo is a significantly higher level than level 15, or your Kiyohime has a higher level buster up, or your Kiyohime is max-foued, then you shouldn't need to use the Stalking trick for the first wave. You should clear it with just the noble phantasm.