It might be easiest for you to get help from PG Music.
I don't know how big the MegaPak is. As mentioned the other day, the EverythingPak is around 135 GB. With this in mind, 50 GB for the MegaPak might not be enough.
When I read your above post, it wasn't clear in my mind what you are attempting to do from which drive to where.
You mention an f: drive? Is this your USB drive?
Also, when you copied your f:\bb files to the e: drive, how much space was left on e: afterwards? (I'm guessing that this is where you want to install BIAB.)
Are the files in f:\bb a result of your installation or are they the installing .exe files?
Are you still using your flash drive at any point?
May be it would be easier if you can answer the following...
1. On what drive are the installation files?
2. What drive do you want to install BIAB on to?
Lastly, the minimalist install is for someone who installs from a USB hard drive and wishes to run the program from that USB hard drive. This is probably not applicable to your situation with a flash drive.