As you said, the Load-Master instructions are not good, and the setup can be a nightmare for a (novice) reloader.
1.
See the videos at loadmasterzone.com view them carefully, now. Here is the link.
2.
Use the LoadMasterVideos.com forums for specific help, or use this forum here. Many questions about the Load-Master setup have been discussed here (as Nate1778 knows
. To find those discussions, use the search function on the forum pages--first to search this (sub)forum, and then to search a specific thread. Enter searches such as "LoadMaster," "Load-Master," "Lee Disk," "Auto-Disk," and so on. Careful study of those results will help acquaint you with the issues involved with these products.
3.
The question you asked about selecting the disk for .45ACP suggests you may not have a scale. As Nate1778 said, get a scale--and yes, the Lee scale does work fine, once you know 'the trick' to using it.
You can use the auto-disk instructions by 1) selecting the powder you want to use (hint--try Winchester 231 to begin with), selecting your bullet, and then using the Lee charts to determine a disk size for that type and weight of bullet
with the powder you are using. With a full measure, you should be safe. Many people, including experienced reloaders here on this forum, are successful with the disks.
Personally, I preferred early on to get an Adjustable Charge Bar and use the techniques one uses with a scale and direct measurement. Set the bar, weigh a charge, adjust as needed to get the correct charge, and then verify it, and so on.
Your post doesn't really indicate whether you are a novice reloader or merely a new progressive / Load-Master reloader. Tell us a bit more here, and you can get some decent help, I think. Just return here, to this thread, to ask those questions....
Jim H.