First to remove fixture from a sequence can be done in a few different ways.
From tracking sheet where u can manually select atributes you want to manipulate and with two finger tap open the calculator and from specials select remove.
Or you can use store remove witch in your case I would use. So select fixture by selfix twice to active all atrributes used by that fixture, then store/ remove from the sequence you want to remove it from.
Same method goes for presets groups etc.
For store problems I dont fully understand how you are storing atm.
But still if you don't use presets at all that would be a great place to start. Example you can use All presest to store looks or use other preset pools and combine looks from there. Then you could easily mix and match presets for each sets and keep them in line shen you modify and uptade the presets only.
And from store options I only usually only use source programmer and status active. That way I always know what I am saving just looking in the fixture window.
Hope you can get something out of this and its no too difficult to understand.