You can program long notes quickly on the BSP by pressing and holding the first step button of the note, say step 1, then hit the note you wish to extend followed by the last step button of the note, which would be step 16 for a full 16 step length. In practice, to do what you want to do you would program the first 16 steps with your root note then switch to the second 16 steps and hit the note you want to follow. It's not really transposing the sequence though, more quickly programming two long notes into a 32 step sequence.
If you set your SQ-1 as the master clock (internal mode) and MIDI channel 1 (if seq 1 on the BSP is also channel 1) and your BSP to MIDI sync, the SQ-1 will then send it's notes to the BSP and transpose SEQ1 according to the pattern it's playing. Set up your two sequencers in this fashion then press go on the SQ-1 then have a twirl.
As the SQ-1 is only a 16 step max sequencer, you won't really be able to transpose a section of your BSP sequence due to that length restriction so maybe try the Keystep? Do the same thing regarding making the Keystep the master and setting it to channel 1, then program 16 steps of middle C followed by 16 step of a note the same interval from middle C as that you wish to transpose the sequence by. As you can do the full 64 steps with the Keystep as well as vary the step speed division, you'll have way more success. Again, plug them together via MIDI and have a go and see what happens!