Thanks to Tux for the tips.

I'm going to start playing on Huge unit size, but with the absolute lowest possible graphics settings and the lowest possible screen resolution. If EBII seems 'fast' to me on that setting, then I will incrementally increase the graphics settings and screen resolution little by little until I reach what seems to be a good balance between frame rate and graphics detail.

(Although graphics detail, for me, is the least important aspect of EBII.)