oh good-- i totally understand the whole 'make the kid happy' thing' i've done enough graduation, birthday and wedding cakes for mine -
but i have to draw the boundary that disco dust has no place on food for any age although in the same breath i acknowledge it is your decision--an alternate idea is to use a dummy cake for the top tier (or at least discard the top tier) for safety's sake and the health of your guests ;) as it can sprinkle off--something to consider is all--
i'm delighted hat i helped you and glad to be of any further assistance if needed
if it goes well and you feel like it--i'd love to hear about your adventures with the pate choux--i think you're gonna be pleasantly surprised
btw--i think i bake at 350 or so--i turn the heat up & down i'm sure-- depends on the thickness
i've written entire bible verses with that stuff--i haven't done tons of super high vertical but jacques sure did--well i guess the fireworks weren't short either in fact those were just stuck into skewers--
what about a revolving cake? cake revolving quietly in the candlelight---c'mon, mom !
best of the best to you!