Best setting for Allnic H-7000 phono preamp with Hana Umami Red MC cartridge

I've had the H-3000 for some years and used various cartridges, including Airtights and Koetsu stones. The Airtight has a very low internal impedance, and sounded best loaded down. The Koetsus sounded better with a higher impedance setting. Given the ease with which you can adjust these settings, you should experiment. 
Enjoy your new equipment!