High Pulse current cable inductance

Hi, I am trying to reduce cabling inductance to transmit high pulse currents of the kind laser tubes require.

https://www.electro-tech-online.com/custompdfs/2013/06/TN36000-2_Cabling_Effects_IX.pdf

Is it true that replacing a single 4awg cable with about 4 x 12awg cables twisted together will be a lower inductance solution with similar resistive effects?

It won't have significantly lower inductance but it will have less skin effect resistance.

To lower the inductance you can use a flat copper conductor, as discussed in the ap note you referenced. Why not use that cable for your requirements?

A cheap and dirty approach for this would be to use large braided ground strap wire, such as this. The return line should be the same type of strap as the pulse cable and laid with the flat sides as close together as possible to minimize inductance (with some insulating film or tape in between them of course).