I'll just put this out, SaGoZo is the Titan/Heat-Metal. My money is on the dinosaur being the FJ style form, with the final form being Multi-King or something. Or hell, just the bird medals.
So far the combinations are just parts swapping i.e. adding elements of the true alternate form to Tatoba. So I think it's very likely that the full colour forms will be the equivalent to standard form changes, because they'll alter the powers and abilities of the whole form, not just the legs or the arms. So SaGoZo is the big slow form and RaToTh is the speedy form. I don't think we'll get the FJ style big jump in power proper until we see either the red form or the dinosaur form, if that's still in the running, and with the Pteranodon yummy confirmed...