in the tropics, when is the best time to prune frangipani?

Answer 1

Transplant Frangipani or prune them when dormant in the cooler months
http://www.frangipanifarm.com.au/history.htm
You might find the link below interesting
Facts About Frangipani
http://www.theflowerexpert.com/content/aboutflowers/tropicalflowers/frangipani
This is just one of those beautiful tropicals that we can't grow in my state.
Good Luck!