The B45 is a Bronze, 600 Watt Dual Frequency 50/200 kHz Transducer. And keeping in mind that Squid are very hard to detect due to the nature of them being soft-bodied, no bones or any swim bladders, and filled are with sea water. So, they barely mark on a typical fish finder.
You might see is a blue fuzz when a school of squid passes under the boat.
So you want to use the highest frequency available for use in squid detection, and I recommend setting the GP1871F at high frequency of 200 kHz or greater. The when fishing for squid, the commercial fishing uses sonars that are 240kHz.