Hi Serenity,
Unless you have a technical electronics or engineering degree and the electronic gear to plug in different component values and graph the changes in frequency response and crossover slopes, it's impossible to estimate what effects the substitution of different components will have in a particular crossover design.
I recall watching Ian test different values of crossover components in tweaking the design of an Axiom speaker, and subtle changes in the component values gave the speaker an entirely different midrange response when the speaker was measured and then tested in double-blind listening tests.
The speaker might have been the early M80ti, whose midrange response I was highly critical of (edgy and sibilant on female vocals and brass instruments) and wanted him to change, which he did.
Good luck (and you'll need it) on the home-built speaker design.
Alan
