I am still confused to this day why people still refer to jamps as dwarfs? Ive seen them well up in the 15 16 foot range and theres nothing dwarf about a 15 foot retic. All three snakes you listed are all very different from each other. Out of the three I think the burmese are the best "starter" giant if there were such a thing. There alot more relaxed then retics and anacondas. Retics are always on the move and the pure power anacondas have are insane. Sometimes we struggle to get our anacondas back into there cages. My female green likes to wrap the end of tail right around your hand and just hold on. Shes 7 feet and feels more powerful then our adult male retics.