Gleim is fine. The difference between Gleim and Becker is that Becker focuses on just the important items. The goal of Becker is just to get you to pass. You're more likely to score in the 75-85 range with Becker, but studying is easier and quicker.
Gleim is just everything and can be overwhelming in my opinion.
As already is said, I highly suggest starting with FAR. FAR has some overlap with all the other sections, especially REG. Then take REG and then BEC and AUD last.
BEC you can cram for. I studied just for 3 days and finished the test in less than an hour.
I can't give you advice on how much you should study since everyone is different. I could give you an easy plan for Becker (watch video section, do questions, watch video section, do questions), but I'm not sure how Gleim is structured. It's been a while.
I'd say spend a significant amount of time on FAR b/c there is SO MUCH information and only a 75 question test. This is a test you do not want to take again. Everything else is pretty easy to study for (except maybe REG).
If you want to get a 99 (a perfect score), you probably need to study 120 hours per section. If you want to pass (75), which is all that matters b/c no one gives a crap about your score, put some effort into FAR, figure out how you did and adjust the amount of studying for the rest of the sections.
Zach, CPA, CFE