ToME: the Tales of Maj'Eyal

So, on my twelfth run through it and just wondering:

Does anyone have tricks to avoid or reduce the lag that is omnipresent in the area?

Not asking for tricks to get through it or make it easier (I know them), but pretty much every action in that dungeon is followed by a spike of lag as it prints out and updates the screen for all of the moving sand tunnels, even the ones offscreen. It makes it one of the more tiresome levels to march through, which is sad indeed as its both creative and has a not to be missed reward set.

I know it's a well known bit that it does it, but I haven't seen any thoughts on how to avoid it.

Exiting back to the main menu and reloading the character appears to flush any leaked memory out and improve performance.

It sounds to me like you have enough experience with the game to know what's going to be overpowered or cheaty. Just look. Most that are overpowered (such as homosuperior) flat out say they are. Outside of those that are explicitly intended to be overpowered I don't think I've used any addon race or class that felt more powerful than just playing an oozemancer.