I'm just curious to know about whether it is possible to stick a sequencer inside another sequencer so that you can get more magic although it would be of a lower level. I can't try this out for myself yet you see because I'm too low a level and at the minute I've only got minor spell sequencer.

Nope. If you cast a sequencer in another sequencer, it'll just bring up the sequencer creation menu during the battle, which you probably don't want. The sequencer triggers appear in the innate abilities menu, and you can't add innate abilities to a spell sequencer.