Hello Wishmaster
I have rigged pre constructed kits on a couple of occasions, I will first have to repeat what Edo said and that it is a lot easier to plan it before assembly so you can drill holes in the appropriate places and either put in turnbuckles or thread monofilament thru (the two methods I use, although there are more).
How I would go about it would be to use very thin copper or fuse wire, this can be found in phone charger wire or TV aerial coaxle, I have a drawer full of copper and fuse wire of all manner of widths. I would then straighten it, this can be done either by spinning a length in a drill chuck while the other end is fixed to something secure (it only needs to rotate about 20 times to get completely straight) or for short lengths place it between two plates of glass or two steel rulers and roll them backwards and forwards (I find that method quicker but a bit hit and miss). Using dividers find the lengths needed and cut the wire accordingly gluing in place with white glue. As for the double wires I rigged a completed Smer Avro 504K and for ease I did single wires all round (OK all you AMS sufferers chastise me if you wish) but it looked fine in my opinion, mainly because it was a vast improvement on having no rigging but also because most people other than AMS suffering WW1 modellers would not know any different anyway. As for the tail boom to be honest I probably would have done this method for them anyway because I would hate to have to drill that ultra thin plastic. If you wish to add a little realism but give yourself a bit more work you could always heat stretch a hollow plastic tube like one of those pen refills or cotton bud stalks and chop off lengths of about 2mm, slide them into the middle of the wire and then when it is in place slide the two shrunken tubes to either end so they look like turnbuckles. Paint copper wire dark silver and turnbuckles if you do them brass/bronze.
Hope this helps, Alan.
