Gezzz, I don't know where to start. OK, here goes.
1. The reason I don't use my Pro Conversion kit, is that I like the Standard Auto Disk unit, because it does not use a "wipe" and it holds less powder. It is plastic (base of the powder measure) to plastic (the disk or adjustable disk that I do use). The "wipe" is a small foam disk that sits at the bottom of the Pro Auto Disk resivior and between the disks. If you leave a disk in the powder measure with or without powder for any length (days, weeks, months) of time the foam compresses and needs to be changed out. With the type of reloading I do, all I have to do with the Auto Disk is set it and forget it, it is just that simple. With the Pro Auto Disk, I would have to remove the disk after each session to make sure the "wipe" did not get compressed and stayed fresh.
2. While the Pro Auto Disk holds twice as much powder (almost a pound)than the smaller Auto-Disk it comes in handy if you are reloading RIFLE becasue you are using more powder. I only use it when in a rush and I want to load up a lot of .223. I find that I use less than half the powder in the Auto-Disk during a reloading secession of 100 rounds of pistol ammo (5.6 grains of W231 at the most.) For .223 I use 25 grains or less of H335 or H4895 or recently IMR 8208. Different amounts needed. However to get the higher amount of powder into the case you have to use the "Double Disk" set on the powder measure, and yes I do have one and have used it and it works very well.
99.999999% of my reloading on the Lee Classic Turret press is for PISTOL and very seldom do I need more than 13 grains of powder and that would be for .357 mag. All the rest of my loads are between 3.8 grains and 7.8 grains of powder. (.380, 9mm, 38 spl, 357 mag, 357 Sig, 40 S&W and 45 ACP) Therefore, I always use the adjustable disk since I tune in my load to exactly what I want. I do not need to mess with the disk sets since I can adjust to EXACTLY (not even a 0.1 grain off) what I want to use. It will throw a charge 98 % of the time not even off 1/10 grain and since I never load to max the 2% that are 1/10 higher I do not even pay attention to. I still measure every 10th or 15th load just to make sure, but it has been a waste of time, I just do it for safety sake and always will.
Now rifle, I load completely different because of case prep, sizing, trimming, priming and for a powder measure I use a RCBS Chargemaster 1500 and each round is not even 1/10 off. Different method of reloading and for that I use a RCBS Rock Chucker for my press.
But as to the Auto-Disk and Pro Auto-Disk they work great and save a lot of time on a Lee Classic Turret or any other of their presses including the 1000 and the Load Masters.
I have had mine working every week for the last 6 years without a problem, some day I will have to replace it just not sure when. But when it comes it will be replaced with another Lee Auto-Disk.
Hope this helps.
Jim
Just so you can see what I am talking about: