Youll need to protect your decals, so Mylar would be the best way to go for this.
Im dead against CCing a PF unless you really have to - if you do a restore using paints then itll have to be CC'd.
The game is a keeper and will not get a high amount of play on it compared to on site. As stated earlier, polish and clean balls is the best way to protect against wear. These precautions were never done on site and so Mylar was the preferred way to protect as its quick and easy and cheap.
A PF doesnt have to be floorless - amounts of wear are to be expected and show the games use.
CCing is permanant, so bear in mind that later down the track, a better option may become available to you for a restore.
A full Mylar is no problem, so long as its kept out of the sun and not allowed to bake on - you should have no problems removing it in the future - especially over diamond coat. You might find that the inks on your decal will fade over time and it will need replacing.
With any restore - only do what is necesary if possible and gentle steps are way better than the jack boot
