Choosing between scripts when writing in a hurry

I recently attended a talk at a local shrine where the speaker was moving so quickly I had to make a sudden choice: stick to kanji or switch to kana. I found myself scribbling kana just to keep up, but later I struggled to scan my notes! In your experience, do you prioritize speed by using kana, or do you find that certain kanji abbreviations are actually more efficient when things get busy?