I have had success also using the shorty packs ( I use the promatch). It is a snug fit left/right and you won't be able to use the electronics trays (NBD) I just removed the top deck, drop the pack in, reinstalled the top deck and added a small blob of shoe goo in front of the pack. it's not going anywhere.
I just double side taped my receiver and speedo to the battery in their original locations.