Breast compressions--good. Check Kellymom on how much milk is common to get, it's something like 1/2-2oz (convert ot metric if needed) per pump session is a sign of an abundant supply! The quantity needed for breastmilk versus artifical milk is drastically different, because the more product a baby needs, the higher the manufacturer's profits, so formula-fed babies need mroe formula than bf ones need expressed breastmilk. Count nappies and you will know how things are going. Kellymom has a nappy count tool in one of the three links I just replied with.
Try pumping at approximately the same time every day and within a few days your body will 'figure out' that you need a lot of milk at that hour and will increase output. Your double pump is going to help too, as it's suspected that double pumping releases even more milk more quickly than a single pump. A hand pump is not suitable for anything other than going out for short periods very infrequently.
Going longer between nighttime feeds--I don't understand the logic of that if you are trying to increase LO's weight and your supply, but I *can* understand pure exhaustion and being fed up with feedings. Consider sleeping safely with your baby to increase your milk supply and reduce a little bit of the daytime feeding frequencies. Again, if it's warm where you're at you might be sleeping with just a sheet, which is a very safe environment for a baby to sleep in. Look up safe sleeping tips by Googling Dr James McKenna or askdrsears and their safe sleeping tips. I am very well rested and always was, even with nighttime feedings that were 4-5x/night. The other bonus is nighttime is when prolactin (milk-making- hormones peak, that's why you have the most milk first thing in the morning. If you take advantage of that and do several nighttime feedings your prolactin will go up even further.