It seems like the build server contains only an image of the firmware version 3.0 for the my net n600 not the n750. I can try to compile it myself, which I might just do for the exercise anyway following the README instructions: https://github.com/sudomesh/sudowrt-firmware

I'm assuming this config needs to be edited, will probably look into the openwrt build docs as well: https://github.com/sudomesh/sudowrt-firmware/blob/master/openwrt_config/arch_configs/ar71xx

Thanks,
Matt