sanding sealer does just what it says.. after the final sand, it seals the wood from whatever comes next. Grain filler is only used on porus woods to flatten out the plane. if you cleared over without filler, you will have pores all over in the finish. then when you try to polish the clear, the polish and wax will get stuck in the pours and turn into little white specs ( happened to me before)
You will need to fill the grain on this one.
What kind of clear coat are you using? I hear lots of people rave about he stuff make by 2K. It dried super fast. On my last few builds I used Deft Lacquer. Although its sprays nice, it took forever, and I mean months, to harden.
You wan to go very light coats of clear to build it up. Go too thick and it will frustrate you later
so get some grain filler, they make mahogany colored filler. apply, wipe, let dry, sand flat, then spray the body with sanding sealer. sand down the sealer when dry. not all the way through though. make sure the area for the decals is nice and flat and even. apply decals then start clearing with light coats. This is gonna be time consuming but worth it. Don't go thick with it. Some guys do a few coats and then sand a bit in between, but I just do it after every can and have never had a problem. Only thing is with the decals, you may have some extra sanding to do as a ridge will form where the decal meets the body. Lets start there for now
we will worry abou the final sand, buff and shine later. Hope this helps!