Copy and pasted from my very old (2006) T39 plans:
Bill Fitzmaurice wrote:
You must use a high pass filter set to 35 Hz and that has a slope of at least 24dB per octave to realize the real potential of the design.
If this has changed, I have no idea. This is the same HP setting for the T30. I stand firmly on my recommendation of Titans over Tuba 30/45. If you absolutely, positively must have a HP at 30Hz, build T48. Don't want to believe just me? Ask djtrumptight, he has both T39 and T48. Ask Monomer, who had T30s and replaced them with T39, and he plays EDM! Even the man, himself, who is/was a bass player in a Reggae band, recommends you only need T39s. Tuba 30 are very good. Titan 39 are a LOT better.
We can guide you, but you have to make the final decision. For what you want to do, and the spaces/audiences you describe, a pair of T39, as wide as you can transport and store, and either a pair of OT12 or DR200/250 is the dream system. Small, lightweight and extraordinarily powerful.