Well if you have 1NQ and look for a 50 point move, you will be able to accept a lower stop loss to see your plan come to fruition. On the other hand, if you have 10NQ your stop will be much tighter and you will not be able to risk changing it (maybe you get in, there is a pullback and u get stopped out, market goes a few ticks down and then goes back to your entry and then touches your take profit, but your trade would not be active because you already got stopped out) if this happens it will also affect you psychologically (seeing how the market touches your stop but then shoots to your profit target will definitely have a psychological effect which might push you to take more risk on your next trade. This of course depends on your account size, your risk tolerance and risk management. Personally, if I see a quick aggressive move coming I will consider taking on the risk of 10 contracts for a 5 point move