Justrade hinted at it but I'll spell it out.
GSX is $87.50 right now. By your description if you open a spread by selling the Sep 18 70p and buying the Sep 18 60p the credit will be $160 (I get a slightly different number but close enough) and the collateral is $1000. So, yes, technically the "max loss" is $840 but that assumes you have no stop.
But you've said you do have a stop at $80.
The worst case scenario is you open the spread first thing tomorrow and the price runs immediately down to $80 where you get stopped out. How much do you lose after closing the trade in this scenario? By my calculations and without taking slippage into account roughly $70.
So without slippage (lack of liquidity, adverse changes in IV, etc.) and assuming the worst price action you are risking 70/2000 or 3.5% of your total stack. If you're cool with risking 3.5% (a little more with slippage) on a single trade and you are confident you can actually get out near your stop then you're good.
Note that if you let this trade go to expiration your break even is $68.40 so while the first day a drop to $80 would cost you $70, this situation rapidly improves and at expiration as long as GSX is trading above $68.40 your trade profitable. If on expiration GSX is above $70 you keep the entire $160 and get your collateral back.
Bottom line
Max gain: $160
Max loss if stopped out: $70
Max loss as percentage of $2000 stack: 3.5%
reward:risk 2.29:1