How much time do you have to begin answering "amen yehe sheme raba..." after the person saying kadish reaches that point? Is it the same ruling as that for answer a regular amen for a bracha (i.e. the same amount of time it would take you to say "shalom aleychem rebbi") or are you granted a longer time span to answer?
The issue arises when you are a bit behind the tzibbur and the chazzan began reached the amen yehe sheme raba part and you are in the middle of a long verse. Do you interrupt whatever you're saying and say yehe sheme raba or do you finish your verse and rely that you can still answer yehe sheme raba slightly later (around 3-4 seconds after the congregation)?