I do not limit my gambling time but I do limit my gambling money, everyday I set up a profit and loss. Daily I set up a $100 profit and $100 loss whatever comes first I stop already. But I think having a gambling time is only for people with hectic schedule as for me I don't limit my time to enjoy and to entertain myself.
Though this kind of things is a little bit hard to achieve and needed patience and practice.
Meanwhile I think yours is a good choice to limit losses and exit once the winning target is reached. If what you do can be consistently maintained, then I think it will make you successful in making this gambling a place to get entertainment. To be honest, I can't do it consistently because I find it hard to stop and exit immediately after a win.