It's good to hear everything is (almost) working out for you! Sometimes it takes a little fiddling with things like valve stem length to get everything just right. I have to warn you that your tube exploding problem was most likely caused by user error. Chalk this up to a learning experience. Sometimes it's painstaking, but once I have the tube and tire mounted, I put a couple pumps of air in and go around the whole thing making sure the tube is not pinched between the tire bead and rim. This makes all the difference and I haven't had a blowout like you described since.

As for the new fatter tires being slow: This has been hashed out and argued repeatedly on forums. These threads and articles on tire width fascinate me and if you like that kind of thing then definitely give them a read. There are a lot of variables that are for you, and you alone, that effect how fast you are traveling. The thing that really stands out to me is perceived speed. Many people think a new wider tire slows them down because they are not feeling all the bumps and road irregularities. These people then actually compare speeds on a bike computer or gps and realize they are similar to their old slimmer tire speeds. But really, who knows, your new tires could be slower, or they could just feel slower. What really matters is they are more comfortable and hopefully they let you enjoy your bike more!

As another side note: If I were you, I would try these at about 40-45psi up front and 50-55psi in the rear. Tire pressure is another thing that takes some playing around with to get just right. I like to use a tire pressure calculator online to get in the ballpark and then make minor adjustments till it feels perfect. It always surprises me how some tires feel completely different with only a 5-10psi swing.