This little hack works very well. You might go even a little further: consider to add a MC68882 FPU. A while ago I ripped one off a dead PB 180 daughter board. If you attempt to take a FPU from a PowerBook, the use of a heatsink properly attached to the FPU is necessary (or you will notice a smell of boiling resin, soon). There are a few application programmes that need a FPU (no software FPU emulator), like DraftBoard.

Note: The LC III supports the excellent Portrait greyscale monitor (as opposed to the LC 475). It makes a nice machine for drawing, text and layout work.