I'm a believer of keep it simple so anyone can fix it,and parts are on the truck. Especially up here in New England..the hi seer doesn't benefit us much cause of the short season. No pay back for the extra money spent.carriers parts are expensive and nobody has it on the truck..you wait with no...
It sounds like you have a motor and pulley with a belt for the fan. Not a direct drive blower. On the motor there is a tag that should give you sfa amps. (Service factor amps). Adjust your adjustable pulley on the motor to this figure test with your amp meter.
I use the yellow one every day it works great. Leave the retention head on insert the gage till it bottoms out on the nozzle set the electrodes into the notch and set the gap it also sets the distance the nozzle is from the head. Fool proof
If you take dry concrete mix and pour it in the crack let it sit the moisture will harden it. Some may say bs but it works. For what it cost to do it you have nothing to lose