It seems you're less interested in Wistan. It's clear that it's easier with him.
However, the idea of letting the right flank shoot at the enemy works, and the losses are generally quite acceptable. You can take about 6 Flies, which is already a lot without a hiding spot. On average, I lose 25-35 Gnolls, 5-6 Flies, and Gnomes.
Overall, considering the possibility of a smaller Medusa Nest and Tazeek's higher stats, the idea is quite viable. I'll keep it in mind.