The potting mix from Weigert's looks great, very similar to a mix I use. This is the mix I would use. This is open enough that you would probably need daily, or every other day watering. It is open enough that even if the soil is still moist you can water without causing the tree to be over watered. It will allow air to penetrate even when wet.
The potting mix from Tropical Bonsai Miami has too many fine particles in it. It would likely hold enough water that your tree would not need water more than once every 3 to 7 days depending on temperature, sun and wind. I would not use this mix. Or if you want to ''salvage'' this mix, you must use a sieve and remove the fine particles. The fine particles are blocking the movement of air to the roots. Use a piece of window screen, ( roughly 1/16th inch mesh ) and shake small portions of this mix on top of the window screen. Throw out anything that goes through the screen. This will improve the Tropical Bonsai Miami mix. They probably use this mix because they can get away with watering only once or twice a week. When you have to pay someone to water, if you can skip a few days, you save money. So that is probably why they use this mix, it lets them reduce labor costs.
If you know you will be traveling, and can not have yourself or someone check your tree for water daily, you can use the heavy water holding mix, if you can figure out when to water. Once you know the patter (use your finger, or the bamboo skewer, or the moisture meter) you can then take your long weekend without worrying that the tree will dry out totally in your absence. But personally I would just use the Weigert's mix.