I dumped my Power Mac 6500 ROM and tried to use it in SheepShaver. I failed miserably, so good luck to you. IIRC, the ROM is 3 MB.
Do you want a file splitting program? I wrote one for situations like this.
Do you have a ZIP-100 disk around? Just use it. If not then...
...my recommendation: setup an FTP server on the G3. Use Anarchy on the 6500 to connect to the G3 and transfer files to the G3. From there, copy the files from the G3 to a USB drive. Then connect the USB drive to the MacBook.
For future reference, what version of the Mac OS is running on the 6500 and G3?
As for your Mac SE, your Power Mac 6500 has a floppy drive. Why not use that? Here is a link to System 6.0.x:
http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English-North_American/Macintosh/System/Older_System/System_6.0.x/
And here is a link to some versions of Disk First Aid so you can troubleshoot its drive:
http://download.info.apple.com/Apple_Support_Area/Apple_Software_Updates/English-North_American/Macintosh/Utilities/Disk_First_Aid/
Good luck!