Installation of Chamfer Boards

OK folks I am looking for the good word on the do’s and don’ts of installing chamfer boards.<O:p</O:p
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I have 78x19 Pine Chamfer boards that are going onto a pine frame and had a couple of questions that I hoped you might be able to help me with. First off when I got them delivered I primed them all round with oil based primer and I have read that you should also prime the ends when they are cut however after installing some (small areas around bifolds etc.) this is a huge pain cutting my lengths to size and then painting the ends before nailing them off. Do trades actually do this (as opposed to sealing once up) and if so what is the best method (like cut, paint then leave dry before install etc.)?<O:p</O:p
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Tradac recommend min fixing size as 60mm x 2.8or9mm however I have 45mm x 2.5mm ring shank nails and after testing these boards aren’t going anywhere fixed with the 45mm nails (2 nails per stud as recommended) so can I use the 45’s or should I stick with Tradac’s recommendation of 60mm? What do you pro’s use?<O:p</O:p
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Nail gun Vs Hand Nail? I had been hand nailing them using 65x2.8 bullet head nails however as per above I have some 45x2.5 ring shank coil nails. Which to use? I have found that the hand nailing takes me forever however after coating them with another coat of primer they look pretty good so could jut be painted over however my coil nailer isn’t giving me the most consistent depth of drive so I have some punched in (varying depth) or others left proud (which I then hand nail) – aside from those that are spot on of course - so after a quick coat of primer it looks a mess compared to the hand nailed section. I have read however that if you plan to paint - which I will - you should punch the nails and fill/sand before painting. Is this what the pro’s do? Again it seems like a lot of effort although I concede this would give the best finish so should I hand nail or gun nail (and then prep it prior to painting)?<O:p</O:p
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Hmmmmmm, that’s it for now and thanks in advance :D <O:p

Ends need to be painted as endgrain is where water is most easily absorbed. Painting the ends after the boards are up will be difficult as they are generaly butted up against the stops.
The general rule for nails is the length should be 3 times the thickness of the material they are holding up in your case 3 times the thickness of the chamfers.
Whether you gun nail or hand nail you should punch and fill for a better finish and to protect the nail heads.