There is the very important distinction between those wires that conduct the full battery current on discharge (also on charge), and those that are only there to balance.
In general it is a good idea to go with very high current rating for discharge cables, such as B-, P-, or the wires that connect of the series cells to each other (I guess the thick red and black ones from your photo).
For the balance cables B1+ etc it is the opposite: looking at the specs of your BMS, it has a max balance current of 60 mA. So I would be a good idea to go with cables that are rated for few 100 mA. The only reason why there could ever be much higher current through those would be a short, and in that case if you are lucky the cable fuses out and prevents your battery from getting damaged or even catching fire. For cables like that going far above what is needed, doesn’t make it safer.
You mean you bypassed it? But why get a 150 A BMS then? Or am I getting this wrong?
Be careful with the discharge. Your BMS is fused with 150 A, but I doubt that your discharge cables can take that much. This wouldn’t really be ideal, since your cables are a weaker link in the chain than the fuse. If you bypassed the BMS, I would suggest to solder in a fuse at some other point. I also have a bypassed BMS but I have a soldered a fuse right at one of the battery terminals.
For the discharge cables it really depends on your setup. They need to be able whatever you’ll set as combined battery current for all your ESCs.
What are those cables in your photo rated for? How does it compare to your setup? I guess you’ll be fine unless you run 4 extremely strong motors with strong 4 ESCs. With two VESC4 you won’t melt those cables for sure. Four VESC6 without extra care would be a battery fire waiting to happen.