I would only take it if I were:just think it might be an interesting discussion, to hear different views...
1) consistently profitable in different market regimes
2) my trading can be easily scalable to utilize the loan
I would say up to 10%. If you can’t make at least that, no point trading.
My friend asked me once if I would consider trading his money and I said : “Until I can trade consistently, I can’t take your money. Once I trade consistently, I don’t want your money.” There are exceptions to that, but for most non-professional traders, I would be interested to hear why this doesn’t hold true.