which would've concluded in, buy a sky3ds rather than CN and you would've been able to use it to boot both systems rather than just the one, and if/when you swapped your region to US you would've been able to use it on that too without waiting X amount of time
yours is one of the only cases where i would say buying sky3ds would work out better for you, the cost of 2 different regional copies of CN/OOT would end up being about the same price if not more than a sky3ds, plus you would then want to change the JPN console to US making the japanese copy useless and you would then need a US copy of one of them