Just graft different grumi onto it (flowering/fruiting), and you should be good to go. Our tree is over 10 feet tall and haven't even noticed blooms yet. Seems grumi can take its time when it comes to flowering and fruiting.
Yes, 2 eugenias are usually better than 1. Sux when you win an auction for the latest uber rare super tasty eugenia, and then realize you probably need another. My hope is to cross graft trees, keep one multi graft of each species, and trade/share/sell the other(s).