Every body responds differently to the effects of carb surplus to this degree, my question would probably be what type of carbs & how do you personally feel after eating it & what kind of shape are you currently in? These are more "feel" issues imo, personal to the health of your digestive system & current condition of your body..
I assume we're keeping it primal with the nightshades & fruits in this refeed?
I don't think any particular number or amount is necessarily "unhealthy", pending your ability to burn the fuel, use it positively for energy.. My context clues lead me to guess you're a younger male? if you're young, already somewhat lean, don't feel miserable after eating a ton of carbs, I'd eat up..