There are some inserts where the black circle around the insert has worn and I am tossing up whether to leave it alone, touch it up using a Sharpie texta or sand it off and use my insert decals that I got from Classic Arcades.  Any advice would be appreciated guys,  If I sand back the insert I may just attempt this whilst the insert is still in the playfield as I do not really want to remove these.  Any experience there would be great guys.

Also, there are two small wear marks at the top of the field that someone has tried to touch up with a texta.  I can live with them as they are small but wondering if a decal printed into clear sticker paper would come up good.  Anyone have any luck doing this in the right colours and to scale on a Spacies before?

Depends on how far you want to go and how your skills are, the decal would be my last resort, I would use an artists brush with long bristles and do the touchups by hand, colour matching as I go, mix paint and paint onto a small piece of card then use a hairdryer to dry fast then compare to original colour, use some automotive clear coat to lock colours in.  But if you would rather not do that you can get reasonable results with the sharpie, just be careful if you want to clear over the sharpie ink as it can bleed and make a real mess.