Usually I just throw them in whatever direction suits me and then react to their DI. F-Throw and B-Throw are pretty wonky when it comes to the sending angle.
When my input just so happens to be forward throw, they usually are DI'ing up and for some reason doing that on a forward throw sends them straight upwards. The DI might not actually be up, but I've noticed that I'm sometimes throwing people directly upwards off of a forward throw. Regardless, if they go above me I can Up-Air > Up-B > Up-Air > DJ > my choice of N-Air, F-Air, or D-Air depending on position and enemy fall speed. A simple N-Air at high percents works too though. When they go in front of me like they're supposed to, N-Air works on heavies at lower %s and works well for keeping them in hitstun for further attacks. On not-heavies or mid %s F-Air flub can keep them close enough for more stuff. Otherwise a good F-Air KO's pretty reliably. Side-B is also an option if you wanna go for it, I really recommend this if they got thrown offstage. Even more reason to do so if you know the next hammer will be an even number, it gimps pretty hard and offstage there's nothing that they can really protect themselves with.
Back throw on fast fallers sets up for easy chain B-Airs. They might still go directly upwards depending on DI but this is unlikely because they'll typically be DI'ing into you and will end up getting some distance off of the throw.
Down throw is hard to use effectively when the opponent techs but DACUS really seals the deal if they try rolling away. The same opponent rarely falls to this twice though and will learn to do something else, usually stationary teching into shield/grab. I love it when I can read a roll towards me because they usually find themselves in the middle of an F-Smash by the time they can act again. SHUFFL B-Air works better for combos though.
Up throw is difficult to influence and is fairly consistent as a result. It also grants the most combo options and is usually what should be used in nearly every situation.
