Request for strategy: Late game tips

[jutetrea]

Kind of random, but question on pricing.

So i've got a good spot in one game where i can become somewhat of a merchant during a peaceful time. I offered prices of 5 pays 7 if same gemtype, 8 if other gem type. for example clam costs 15w+5N so would be 21W+7N to pay or 32 misc gems.

Too high? Too low?

First time i've done it so just curious. Some items will take my pretender to build, which hurts research, but I'm doing well in research in the game (1st currently).