Mr. adg101
Welcome to the thread. Good luck with the cables DIY. Regarding your speaker cable requirements (DF is 250. My speakers are Aerial Acoustics 7B’s and my speaker cables are 8ft long per side) you need a 2 AWG. A 0 AWG will be also fine.
What is the thickness of the cables you are currently using?
Bi-wire as you use it (short jumpers and one cable) is the best. Keep it this way.
EMI RFI
No speaker cables need any EMI/RFI treatment. The Amp's output impedance is so low, that it is like a short circuit to GND, from EMI/RFI aspect. The twisted pair however, may cause some capacitance and inductance while two separates won't. (I explained it down this thread already). There will be no noise issues with the speaker cables I offer (for you to DIY).