Lighting – Adapting Halo H71CT for 12″ joist centers

I have those exact cans and they are adjustable. Take out the bulb and remove the trim. Inside you will see two or three wing nuts. Loosen these and raise the level of base to the desired location. If the base is raised all the way up, then indeed your bulbs are too long for the trim you have selected.

Also note that every trim adds a different depth as well. Trims like eyeball sockets are much deeper and may solve your problem. I suspect yours is a flush mount one, and thus the distance to the base is shorter.

The fixtures you linked to are absolutely fine for new construction sheetrock ceilings. If you are going to use suspended acoustical tile then you will need a different model fixture that mounts directly to the tiles, not the floor joists.

In either case, you can lamp them with CFL bulbs which will burn cooler, less electricity. The only disadvantage to standard CFL's is that they can not be dimmed with an inexpensive incandescent dimmer. Always be sure to match the dimmer and bulbs correctly.