Look at the buoyancy when empty -- it isn't different. Buoyancy when empty is the key, because that's what you have to weight yourself for, in order to hold a stop at the end of a dive, when the tanks are nearly empty.
What a tank weighs on land, and what it weighs in the water, will be different, because the tank displaces water and therefore the water "buoys" it up. 130s are physically bigger than 100s, and displace more water, so although they are physically heavier on land, they are NOT heavier in the water WHEN EMPTY, which is what you care about. They are heavier at the beginning of the dive, when full, mostly because they have more pounds of air in them -- but you are going to let that air go out into the water during your dive, so you'll be getting lighter and lighter. At the end of the dive, you'll be just where you were with your 100s.
Do not drop weight. You might find yourself in an actually dangerous situation, where you cannot control your ascent.