Is this the problem you're describing in this old thread?viewtopic.php?f=20&t=9543&p=58346
Since the file sizes are identical, it seems to me that the resource fork information isn't being lost – aside from the Type/Creator data. If that's the case, then instead of using DropStuff, you can just use ResEdit or even Type Resolve (from https://emaculation.com/doku.php/68k_software
) to restore the Type and Creator data (it's literally just eight text characters in total) when you copy the file into Sheepshaver.
Alternatively, you can use MacBinary II instead of DropStuff, or even Compact Pro
. I think they're both genuinely free at this point.