Kimber 4tc good enough?

try some 8TC, if it doesn't sound better, should be easy to sell for what you paid...maybe the dealer was afraid if you were told you needed more expensive wire, you might not buy the speakers...clearly the dealer likes the bigger stuff...

how long is your speaker wire run?

Mr. steve 59

Your Hegel H360 has a DF of >4000! for 7ft length, you need 16 times (in parallel) #0 AWG cable. Not very likely you do it. but you may...
Any way rather than look for some branded #12 AWG or less thick cable, do yourself a favor and gear up to the thicker you can get. For 4x 0 AWG, you may use a connecting bloc and at the end, a short #8 AWG that would fit most banana plugs or spades.
By ignoring this, you will use only a small friction of your Amp’s capabilities to drive a speaker at perfection. So do the math, a #12 AWG cable is about to use only 1/288 or 0.34% of what you invested in your gear!

That's umm, how do you find the math for that? I will start with a heavy guage for the bass and keep the 4tc for top octaves bi wiring.

One option is to run 8TC for the bass and 4TC for the midrange/tweeter. Bass drivers (woofers) are current-hungry and the larger gauge 8TC works better.