25% collateral because I need some security in all this.
The above reads like paranoia.
You'll need collateral worth more that the loan. If someone gave you about 10 ltc collateral for a 1 btc loan, they could default and make a 0.75 btc profit. You should also have an escrow hold the collateral for you if you want a chance to be taken seriously. You have no reputation and should not yet be trusted with anyone's money.