For me, this mold shouts "life quote, life quote" when assembling the packaging. I'll present some ideas in the next week. It's somewhat tedious to pour the layers, but my incredible workers did a great job. Some are just learning the tricks of the trade. I love that they are so willing to learn.
You absolutely need the injector tool for this mold. Slow and careful is the best advice I can offer. Using strips of blue painter's tape around the edges of the pouring around (base of tree) may assist in avoiding over pours. Once color sets up, remove tape and continue pouring remaining colors. Dental wax is another option for a sealing edge of intricate pouring areas.
My daughter was all over the black and white Tree of Life. I'm thinking that incorporating mica flakes or white sparkle glitter at the base of the mold (to resemble snow) would be even more awesome.