Sounds like a fun project. What is the preferred clock speed then, 1MHz? And how is it being programmed, with an ICSP programmer? I typically use ICSP for anything less than 8MHz, which means no bootloader. Below is my boards.txt entry for a 328P with factory-standard fuse settings, i.e. using the internal RC oscillator @ 1MHz as the system clock.
uno1.name=Arduino Uno ICSP @ 1MHz
uno1.upload.using=usbtinyisp
uno1.upload.maximum_size=32768
uno1.bootloader.low_fuses=0x62
uno1.bootloader.high_fuses=0xD9
uno1.bootloader.extended_fuses=0x05
uno1.bootloader.path=atmega
uno1.bootloader.file=ATmegaBOOT_168_atmega328.hex
uno1.build.mcu=atmega328p
uno1.build.f_cpu=1000000L
uno1.build.core=arduino
uno1.build.variant=standard