Yes it could matter your best course of action would be to determine all loads connected to that circuit and potential loads to see if the circuit will be likely to handle the additional load. Connected loads will most likely be other lights. You can either identify them and add the wattage or better turn them all on and check the amperage that breaker with a clamp on ammeter then add any general use outlets on that circuit at 180 watts each. A 15 amp circuit should not have more than 12 amps (1440 watts) continuous load a 20 amp circuit no more than 16 amps (1920 watts)
First of all, when you read about a "50W LED", it is certainly saying that it outputs the equivalent light of a 50W incandescent light (although that is often a exaggeration). That "50W" LED actually draws less than 10 watts. This means that it draws much less current and emits much less heat, both of which are the factors that typically limit the allowable light in a fixture.
You'd be able to replace a 50/100/150W 3-way with a lower wattage, even if staying with incandescent.
Second, unless the LED light is marked "dimmable", don't try to use it on a dimmer. You may damage the dimmer, light, or both. Even if the light is dimmable, some dimmers will not work well with a low load: a dimmer that works on a 100W light bulb may not work on an equivalent-light-output 13W LED. They make LED/CFL specific dimmers that may work better.
As for the 130V R40, that is probably a "long life" bulb. Running an incandescent at lower than rated voltage extends its life. Therefore, they make 130V bulbs to run longer on 120V. Just use LEDs rated for 120V.
As for your existing florescent lighting, I assume you're talking about the straight tube type. For a fixture that old, it's probably less efficient that newer florescent fixtures or LEDs but still much more efficient than incandescent. This is harder to replace with LEDs, just due to the area covered. There are LED tubes made to replace florescent tubes but they are still expensive and generally require re-wiring the fixture. These are most often used in commercial applications.
Best Answer
I think you are asking the right question. The transformer should be rated higher than the total load. It would be better to go higher with a landscaping type transformer this one is 12V @ 500W. You don't want to use a switching supply as they have a tough time with loads like halogen lights.