Squadron Signal Books have an edition on the P26. It does have line drawings inside showing the position of panel lines etc, but as triflyer says, what it will also show is just how far removed from scale this model actually is. Stand Off Scale would be a better description.
The 2 most noticeable differences are the depth of the cowl (or Townend Ring as it is referred to in the Squadron Signal book) and the spacing of the main undercarriage.
As for the screws to hold the "bits" on. Try nylon screws instead of the metal self tappers. You will have to drill and tap into a small piece of plywood underneath, but nylon will not vibrate out (the screw actually stretches under load and locks into place.)