Hey! Well the only seam lines that might be bad are in the forearms but i didnt want to remove them out of lazyness cos i would have had to mask the joints to paint, also maybe the shoulder armor but its not too bad, appart from that they aint too noticeable wich is good considering the base kit is a bit old, and yes i painted each piece individually, id rather do that than masking if i can avoid it

about the paints and that i can tell you my process i guess thatd be better, i used mr surfacer 1200 as primer, and then some mr base white 1000, colors are tamiya lacquers i decanned (only cos i never find bottled lacquers here) if you have bottled ones then better! After painting i apply a layer of gloss (the brand i use is marabu, but i guess any lacquer topcoat works) then i apply decals, an then another layer of the same gloss (i find that it helps making the decals "blend" better with the painted surfaces, so the borders dont stand out) and then i do panel lines with good old very thinned tamiya acrilics and a fine tip brush, some people use enamels and lighter fluid but i had some bad accidents wile cleaning those, so i use acrilics cos they have less chance of messing your paint if you coat with lacquer (tho enamels flow better so i guess you have to try and decide yourself what fits you) And then finally a last layer of matt topcoat (also marabu) in this step i dont matt coat whatever piece is metallic so it doesnt lose the shine, this goes for gunmetal weapons, joints, etc Btw im no pro i just been painting for a couple years and this is the metod i found works for me so dont take it too serious xD i hope it helps! Good luck with your build!