The screws for screwed fish-plates also offer another solution to installing jumpers or feeders. I use very small diameter ring tags crimped or soldered to the wire and attached to the rail using said fish-plate screws and a smear of graphite grease or 'copperslip'. This avoids the risk of damaging self and sleepers with heat, can be done in any temperature and can be easily removed for repair or modification, and a small diameter hole in the web is hardly noticeable if a piece of track subsequently gets used elsewhere where a connection isn't needed.
It is also possible to recover continuity by using these screws on slip-on fish=plates. (The hole does need to go through the inside flange of the fish-plate as well, as the tap will need to go far enough to cut a complete thread) However, to a large extent it does depend on where these maintenance activities, as opposed to installation during track laying, are carried out. For obvious reasons the drill, and the tap, needs to be as horizontal as possible which can be very difficult where adjacent track is present, and particularly so at the exit end of points. A small modelers hand drill held with the drive wheel horizontal is awkward but does allow almost correct alignment. And I use a home-made spanner to drive the tap. The presence of fixed scenery, retaining walls, fences, platforms etc usually means, unfortunately, that the track needs to be lifted.