cool, ok i can give you obviusly btc as collateral, how much for thath? i really i do not know how much you want for collateral. please tell me
I have no idear to be honest... Like i said, it's been a long time since i mined on the testnet. tBTC is without actual value, i guess the equivalent of $50 in BTC, LTC, ETH,... would allow me to mine 10 tBTC in case you'd run away?
I have no idear if this is to much or to little, it's just an incentive for you to give the tBTC back once your tests are finished

It's only collateral by the way (not a sale), if you give the tBTC back within a month, you'll get everything back (minus transaction fees offcourse).