My speakers are tri-wired, with the crossovers at the amplifier end. The short (10 inch) cable from the amplifier to the crossover is Cardas 5 nines 17AWG silver, paralleled 4 times for an aggregate AWG of 11. The main cable(s) run eight feet long, each way.

I used 2 AWG 9 copper Litz in parallel for the woofer. This results in a 6 AWG cable

AWG 17 copper Litz, 5 in parallel for the midrange. This results in a 10 AWG cable

AWG 22 4 nines silver 8 in parallel for the tweeter. This results in a 16 AWG cable

I use heavy gauge Rhodium plated lugs, soldered on. They seem to stay clean and tolerate mechanical abuse. I've had bad luck with bananas since they seem to get lose with age. Gold is good but so expensive that the plating is too thin and is mechanically removed with use.

If memory serves all the above was about $500 in parts, not far off a commercial cable and mine is not sleeved and pretty, although I did shrink sleeve the very ends and I had to provide my own labor.

The crossover and cable configuration are the result of many, many hours of listening to various combinations. The only generic answer is that a heavier gauge always seems to sound better for woof, mid or tweeter. My cables gauges were limited by cost.