I have a question about your BR box dimensions. The internal
box dimension seems to be important because they could affect
the sound by a parasite resonance.

From bibliography -the most common approach is use sqrt(5)
"golden" ratios: 1/1.618 : 1 : 1.618 .

Another approach is to use - I think- 1^(x/3) ratios (where x=1,2, 4,5, 7,8,...)
to add only "agreeable harmonic" resonance.

Will another ratios will work fine too ?

Thanks in advance,
O'Tor