Answering several questions in one go......
1. Tesco embroidery scissors......dead cheap, and the holes are fine even for my Cumberland sausage like digits.
2. Clipping and marking takes about 2 minutes to complete (less for experienced hands)....seems so basic it should not need explaining yet comes up all the time at meetings and apiary visits here....should make a 2 minute video. Our youngsters here are clipping and marking bare handed within a couple of weeks of starting here.
3. It does not cause supercedure at any higher rate than normal. Rough handling of the frames is far more dangerous, as is improper use of the smoker driving bees out the door by only smoking at the open top of the box, and causing the queen, especially of 'runny' types, to end up outside and potentially lost.
4. No need to keep her away from the bees for a few minutes after clipping and marking. Just drop her right back onto the comb or onto the topbars and let her go down by herself.
5. It DOES buy time. With a clipped queen they really cannot go till the last minute, often as the virgins are piping away and even starting to cut themselves out. Unclipped queens can go amazingly early if the conditions are perfect for swarming. Have seen them go often off unsealed cells, and occasionally off larvae only a day or two old. Clipped queens never do this.
6. No eggs left is no guarantee the old queen has gone. She MAY still be there if clipped. The slowing down of laying and fining down of the body ready for flight can take place some time before the swarm actually departs, but conversely have seen queens in full lay take to the wing too.
Nothing is fixed in this business. The bees do not play by anything other than their own rules, which can vary from colony to colony and definitely varies season to season.
7. Even if you DO lose a top swarm, unless your colony started off a bit on the small side ( low vigour types can go off remarkably small nests), you will lose secondary swarm(s) (castes or casts, whichever guru you read up on) with virgins too.
An immensely long subject.......could fill a book on its own.