Overall, it's a pretty shitty idea, but it's unpredictable. You mainly need good game sense, adapt according to the situation. If he combines right away attack his eco and at least make him garrison. He will most likely target your eco in return. You can then target the statue, usually they won't have gold for castle air since half the time they've been praying. 4-5 cats beats down the statue faster than 1 charrog.
If he combines later, he can do more chip damage, but the weakness is that he will have a weaker charrog if you damage fire or earth. Chip him, when he combines you could go after the eco again. However there's a higher chance of him getting a castle air. Combined forces of crawlers and miners can beat the weak charrog (maybe poison if you have it). You have higher eco than ele player. He loses.