Take an image of the SSD it will stop you needing to download again all the updates to the OS. It would also let you use up to date(ish) drivers for all your components, (Depending on at what stage you take the image of course). Yes if it all goes "tits up" you can just do a full reinstall followed by updates and the latest drivers, so all is not lost.
I would install, do all the updates, ensure I had the latest drivers, possibly install vanilla versions of my programs/games, then take an image so I didn't have to go through that entire process again.
If there is really nothing of import on the HDD why have it at all? Swap/paging file?
The HDD is just a source of noise/heat and something else to go wrong it will also affect every other component in your rig data cables, power cables , etc physically blocking/reducing air flow...