Usually this test is given with a procedure that allows for 1/8" electrodes.
But some welders are being required to use 5/32" 7018 which is more challenging. This video has a few tips that should help
in this video, you will see tips for Stick Welding a multi pass fillet weld with 7014 along with a cut and etch test to check penetration
One test beats out 100 opinions. Cut and etch testing of a multi pass fillet weld using 7018 stick electrodes
Some welders are being required to use 5/32" 7018 for welding tests.
IF the procedure specifies 5/32" 7018 then that is what you have to use.