Their succulent mix holds more water than the organic/inorganic mix as it has pine bark coir instead of pumice. The advertise it as for acid loving plants but the pH difference is not that much from pine bark 4.1 vs 4.3. I would add pumice or depending on what tree you will be using it on, but being that you are in TX I would use it as it is for deciduous and probably add one to two parts pumice or lava to 3 parts succulent mix for conifers. The only thing I don't like about the succulent mix is that it contains fines of the pine coir, so I would sift those out. He screens his soils for 1/8" to 3/8" with the majority of the particles at 1/4", I have been using his soil components for a while and sizing is very reliable.
Succulent - 33% Pine Coir, 33% 1/4 Bonsai Block(calcined clay) and 33% Monto Clay(1/4 inch).
Organic - 40% Pumice, 40% Bonsai Block(calcined clay), 20% Pine Bark Fines.
Inorganic - 25% 1/4 Pumice, 25% 1/4 Bonsai Block(calcined clay), 25% 1/4 Lava and 25% Monto Clay(1/4 inch Turface).