Load setting for Dynavector DX-20XL

I have a 20 XL that according to specs has load requirements of >30 ohms. I have just acquired a Jeff Rowland Continuum integrated with the built-in phono module. It has two MC setting, one for 100 ohms and other for 400 ohms. Which do you think would be better?

Probably 100, but with only two options doesn't it make sense just to try them both and listen?
In order to change it, I need to take the amp apart and remove the phono board. I was hoping to avoid that.

Thanks for your input.