Ok, you are getting there.
The sensors output Voltages sound close. Have you adjusted the Pots yet?
Before connecting the motor you can measure the Voltage out of the L298 with a Voltmeter to tell if the motor driver is 'turning on' the motors. It is a good idea to test this before connecting the motors.
Instead of soldering the motor wires directly to the L289, solder short wires (the same size you used to wire the logic) to the L289 out to near the edge of the perf board. Then run the stripped wire ends through two hole in the perf board to create a 'terminal' onto which you can solder the motor wires.
I have been following your questions and progress but only reply if I have real advice.