xenon

I'm doing a kitchen remodel right now and trying to set up the under cabinet lights. I'm using xenon low voltage puck lights, which I want to hard wire to a light switch. The lights I've purchased connect to the 14 gauge wire with a transformer, then low voltage wire runs from the transformer...

I need to replace the bulbs in my bathroom wall sconces. On the fixtures it says, "Max 50 Watts Xenon Lamp Type T4." The bulbs that came with the fixture are 50W, but I am having trouble finding replacements. I can get a 40W T4, or a 50W T5. I'm wondering if there is any reason I could not...