I use SpicyTL, biggest upside of SpicyTL over hornresp is that you can model lining the enclosure with fibre/open cell foam, and you have more control over the rate of expansion. I can help you with that if need be, tbh I need to remake/update my SpicyTL video, it wasn’t the clearest and I missed a couple of details. I love that you’re considering a transmission line, really, it’s possible to make one for any kind of driver, you just have to change how you do it, for example a driver usually more suited to a sealed enclosure can be used in a mass loaded transmission line (tapers from large to small surface area). IMO, a transmission line is a better modelled port. Typical port simulations don’t consider resonances in much detail, not the position of the driver relative to the box walls, not the port start to the centre of the driver. SpicyTL does, that’s why I like it so. Ported speakers are easier, that’s their upside, but in the case of everything else, transmission lines can be better in every way except size. In terms of everything else, the only thing with better phase properties and below tuning frequency control is sealed. If the driver is suited, MLTLs will give you tuning well below tuning frequency too which I find very neat.