Hey Jetski-
Yeah..gotta hang in there. I agree with about the lower back machine, I do not feel any difference with that machine either.

Your other weights seem ok to me but only you can determine that. If the muscle fatigues on the 9th or 10 rep then the weight is about right. If it fatigues sooner, you should probably go lighter.

Just concentrate on proper form and you will be fine. Good luck and keep going to the gym...