Second sequencer creative strategies?

I have Erica Black Sequencer, and Mutable Marbles. Love them both. I have not yet tried connecting them to create more variation/playability. But in general my question is: if to use BS as a main straightforward sequencer (albeit quite advanced on its own) - what second sequencer would compliment it and what are the creative ways to use 2 sequencers next to each other?

to a large extent any other sequencer will complement the BS... I have Marbles, step fader, BSP etc etc as well as a BS

things that are really helpful in this are precision adders (maybe a multi-channel one) so that you can transpose sequences (can't remember if you can do this straight into the BS)

a second or subsequent sequencer can be used as a sequenced modulation source as well as more sequenced pitch (if/when you have enough voices)

a cv addressable quantizer can also be used to alter sequences - again multi-channel is useful here

I use a sinfonion as a chord pattern sequencer and multi-channel quantizer (and arpeggiator) and I use a second sequencer (the BSP) to change chord patterns - which I clock from the sinfonion (a gate out on the last bar of each pattern) which means it advances very slowly and can be used to change other things - via a switch for example

since you already have marbles, try creating some short looping sequences with deja vu and use that to control params on the BS. If you use the same clock for both you can get a lot of variation in your sequences. just by way of example, i currently use a Marbles and an XAOC Moskwa II (with expander). I send the Moskwa clock out to marbles, and then the X outs back to Moskwa to manipulate transposition, random amount, overall pitch range, etc.