I checked many other tunes and couldn't find one, in which not only the roll off hits that area, the lowest note to hit under that area seems to be C1 at 32ish hz I make music myself and never went that far tho(which does not mean certain tunes do ). Also I know most Producers and Mastering Engineers cut off between 20-30Hz anyway. So it feels to me as it's mostly more about catching all of the Roll off, rather than peaks, to 30 Hz with the most volume is that right? 

Also for the second question plywood is not really my problem happily I can get to that rather easily. As far as I recognised cabinet size and low end extension go hand in hand, skrams and mini scoops both have a very similar format which I consider to be the best middle ground (also width wise they both can fit a hd15 sideways on top, which is not the case with for example the xoc1 ths). So basically it turned to a question of character for me which led me to do minis. I kinda already tend in the direction of the low end extension won't be that big a deal for me, as it seems more like riding a myth to me (could be a completly wrong opinion which I will regret but whatever, I know what minis can do and that's all i care about). Im just not really sure what's to safest pick (in 2026) of plan and especially driver & this here seems to be the place to ask about that