I have just done a bar in led lighting, the whole bars lighting in watts including emergency lighting came to 300 watts or so.
Main problem with led if mains operated, they use the GU10 fittings that could be changed to normal 50 watt after you have left.
The things I would suggest for insulated ceilings is never put the tranformers up there!
They give off a load of heat,and access to them is often limited.You then have a problem in the cable lengths.
I did a mixture of mains operated and transformer operated, the transformer cable out is non earthed two core, the feed in is twin and earth. 0.50 or 0.75 is ample for the dc side.On the transformers you should see the maximum lights you can connect and this differs from trani to trani,and if they are dimmable. (the mains ones I fitted where not dimmable). If you have to put the transformers in the ceiling void try to give it at least 150mm clearence from the insulation, remember they do run warm if not hot!
I have seen them placed on baking trays before now just to act as a heatsink for them.
