MOT's wont arc very far since they're relatively low voltage (for a HV transformer anyway.) But the arc will be Thick and more white colored, hotter since there's more current flowing. A low current (30ma) 15kv NST will draw an arc about 6 times the distance, but the spark is thinner, weaker and more blue.
Welcome to the world of Dr. Frankenstein.
Welcome to the world of Dr. Frankenstein.