Yeah, go with higher wattage. Sometimes when a machine starts up they draw a slightly heavier current than when just "on".
I have two step-down transformers here that I have had on for two years. One handles my older computer, my VOIP telephone adapter, and electric alarm clock, using a USA extension cord. The other runs my LP turntable and some video equipment we brought over. I REALLY regret not bringing my old metal 1950s Wearing blender.
Thing to remember - if you ever want to use an extension cord on the transformer, it's pretty much impossible to get a USA-type one here. Bring a few. Also, be sure they are not attached to a surge protector as that can cause a feedback loop (?) that can cause either the transformer to trip off, or your circuit breaker to trip off.