Eric--
If you are using an ordinary ohmmeter to measure the contact resistance of your keyboard contacts, be aware that usually these sorts of meters put out only a few mA of current in the resistance measurement mode. You need to have a sufficient sealing current through these types of contacts. If you want to measure the contact resistance, apply your 60 mA current loop through the keyboard contacts and measure the voltage across the closed contact(s). Using Ohm's law, deduce what the resistance is. From a practical standpoint, your measured voltage should be significantly less than 0.5 V
Also, under no circumstances please do not apply any solder to the contact surfaces to build up the "thickness" since this will likely permanently ruin the contacts and will only last a very short while. In this application, solder is worse than useless as a contact material.
I hope that the above helps you in getting your 14 in tip-top shape. You are to be admired for embarking on this educational journey.
73, George W6BN