I haven't bred canaries, but have bred Gouldians.  I don't know whether they are different or not in attitude.

I used small wooden boxes with the upper third of the front cut out.  Hung the boxes on the outside of the cage at the top and cut a small section of wire out so they could enter the box.  This worked well for me because I handled the babies daily from hatch til fledge.  My boxes had a hinged top so I could open it to check the eggs and babies.  I had Vitalites in the ceiling of my birdroom and two warm mist humidifiers. They bred in the same room that my parrots live in.  Had no problems at all. My 5 pairs had about 50 babies in one year, allowing only two clutches per pair.  Only lost a few eggs and one or two babies.  I couldn't sell them here in the boonies of Oklahoma so I sold the pairs to a breeder in the Dallas area.

Good luck.  They are fun little birds.

Annie