[Arran]

 I think I would have just bypassed the original electrolytic caps rather then draining them, sometimes you can solder a short terminal strip to the positive lug and connect a modern radial lead cap to it rather then restuffing. If they are originals A.K obviously used electrolytic filter caps of a decent quality, those wet electrolytics are usually bone dry, and have been bypased by new ones underneath, or have been removed and replaced with newer can type dry electrolytics.  
  I think that one can reasonably complain about the poor construction methods in these later A.K sets, there was a good reason why they shut their doors in 1936 because Philco had them nailed to the wall. I don't think that whether they used the rubber wire makes much difference, if they had used the cloth stuff they would still be a bad design, Majestic, and their Canadian cousins,  used rubber wire and heavy steel too in their chassis, but unlike the A.Ks most are not that bad to work on.
Regards
Arran