from what I understand, you could buy that and extra prefilters (it should come with 2), it should work well with the right setup. (I still dont understand VPD or CFM so I cant help with any of that) Making DIY filters works in a pinch, but its best to work with the proper equipment. as an example lets say a bought filter lasts 6 months, a DIY might only last 2-3 depending on what you use to make it, unless you measure, note down every dimension, and item used in exact quantities, the quality of the filtration will vary. Unless you have no other options, I would just buy a filter and some extra prefilters after research on what your tent needs/can handle. If you already have the inline fan and ducting then you only need the filter. otherwise you need all of it, heres 2 other items that amazon says others bought along with the same filter.
Inline fan from Vivosun:
https://a.co/d/4LEYsxl
Ducting from AC infinity:
https://a.co/d/8eZyolg