If the wiring will fit in the GB you can use it, the problem is that most Speaker wiring has a real thick insulation coating.
What you really want to try to achieve is the largest diameter wiring possible, the larger the diameter the less resistance.
Speaker wire also has the added benefit of being a low resistance wire, some things to watch out foe when using it,
Make sure you do a good soldering job, Speaker wire is real fine, and all you need is one strand to make contact with the GB shell and you could spend hours trying to track down the problem.
The insulation on the wiring is normally a Teflon base, making the cable more flexible, but easier to damage, slip of a screwdriver, pinched between the shell halves, eaten by the pinion gear
, Added care is is needed, but the benefits are worth it.
Good Luck and Happy Tuning !!!