Well, since no-one else answered, I'll give my best suggestion.
A reflective material of any sort at the bottom should really
help distribute more light. Cheap mirrors from a dollar store
may work but, I would probably try something like aluminum foil
or cut an old CD or DVD to the size and shape needed. They really do
reflect pretty well.
I used DVD's as the base for wedding centerpieces a long time ago
and they were admired so much they were all missing at the end of
the reception! LOL
God Bless! Spirithorse
