mamad, 2X Alt will work just fine and is conservative so you can push it a bit if you want. The 737 100 and 200 aircraft didn't have high bypass engines so the idle thrust vs no thrust descent wasn't a lot different.
We practiced dead stick landings in the 737 in the sim and the descent was just slightly steeper. We would just stay a dot and a half above the glide slope or if no glide slope stay slightly high and dirty up to final flaps at 100 ft or so with a little extra speed to get you on a normal touchdown profile. The 737 800 might be closer to 2 to 1 than we were, 2.5 to 1.
We practiced a lot of dead stick landings flying business jets when empty in Lear Jets and Citations to sharpen our skills. If you ever become a Sully one day you will know what to do.
Going from a pilot mill to the right seat is great but you miss out on all the learning about flying you get from doing it a few years in the real world, not with a flight instructor and a syllabus.