Is there a reason you want to go with the 68020 instead of the '030 specifically?
The 68030 user manual goes into pretty extensive depth about how the bus sizing mechanism works. The manual includes some example PAL equations for the byte select logic needed for smaller bus sizes, which I think is pretty much what you'd get out of that application note. There are some minor differences in how the bus sizing works for the 68020 (said differences are mentioned in the manual) but you may be able to use the hardware design mostly unchanged anyway.
(EDIT: Downloaded and skimmed the '020 manual and it looks like it has the same material in it. You might want to sign up to the Motorola support forum and ask for the app note there. Google points to a discussion there where someone found it and gave it to someone else via an attachment, but the attachment doesn't seem to be available anymore, at least without a login.)
EDIT again: I assume you found this PDF already, about interfacing a 68020 to an Amiga?
The 68030 user manual goes into pretty extensive depth about how the bus sizing mechanism works. The manual includes some example PAL equations for the byte select logic needed for smaller bus sizes, which I think is pretty much what you'd get out of that application note. There are some minor differences in how the bus sizing works for the 68020 (said differences are mentioned in the manual) but you may be able to use the hardware design mostly unchanged anyway.
(EDIT: Downloaded and skimmed the '020 manual and it looks like it has the same material in it. You might want to sign up to the Motorola support forum and ask for the app note there. Google points to a discussion there where someone found it and gave it to someone else via an attachment, but the attachment doesn't seem to be available anymore, at least without a login.)
EDIT again: I assume you found this PDF already, about interfacing a 68020 to an Amiga?