Currently, it is not possible to use scaling factors of different bit sizes in the same cryptocontext in OpenFHE because of usability issues, see a related thread Modulus Scale up and Scaling Factor scale up. It can be done, but you would have to change many functions and manually keep track of scaling factors. You could create different cryptocontexts, each with the desired scaling factor, then manually transfer the polynomials from one ciphertext to another and adjust the scaling factors.