the current format hasn't changed for a while, and it probably won't change again. you really should be using it.I know it's much better but I don't want to rename the payload files everytime it get updated (start_NAME, b_NAME etc...). I used to use bootctr9 to boot a9 things but when luma updated to 6.3 it's all messed up because Luma3DS.dat is now load arm9loaderhax.bin and I really don't want to put another arm9loaderhax in somewhere else. I'm using 3 emunands and leave sysnand untouched. It's my tough choice.
Luma3DS re-added the reboot patches for 9.0 FIRM, which breaks running arm9 stuff. this is intentional because of the chainloader which, again, you should be using.
with a9lh you don't need Luma3DS.dat.....
why exactly do you have 3 emunands?