Try this:
The QL data files are all ASCII files, and can be easily edited with Notepad or any other word processor.
Just go to C:\Program Files\QuickLOAD\data\powders and make a copy of the file qloadfw.pro. Rename it to something like "available.pro". Then open the file with Notepad, and simply remove the lines that have the weird unobtainium powders that you mentioned. Save, close, and you are good to go.
Now, in QL, access the following menu item tree: 'Data: Add, Change, Load, Save -> Propellant Data -> Load a powder file'
This will bring up a dialog screen that should show you the available powder files, including the one that you just created. Select it, and voila! You are now using a custom powder file with just your selections.
No risk, as you can always select the original file if you think that you boogered something up.
Or, in windows 7, make the new file and go to
C:\Users\your name\Documents\QuickLOAD\data\powders and open the Qloadfw file. Size it to 1/2 half screen. Do the same with the new file. Then, copy and paste. For example,
"Alliant Reloder-15 ","3990","1.2380","1.620","0.5200","1.5423","0.395","1.6309","0.920","","","","","","","","","","","","26FEB00"[/i]
Good luck,
Bill