Based on one old comment from the 'bt' author (search forum for 'lineplotterindicator') 'lineplotterindicator' was made to quickly show a line. So you may need to make an indicator from 'self.inds['signal1']' to be able to customize it's plotting.
You can load the data using a loop and enumerate data in strategy. Some of the posts that could help you
But not sure of memory limitations.. @vladisld has a post to save some memory
Here are examples of custom loaders for Pandas:
Thanks for your indicator!
How do you use it in order to compute a backtest?
Do you use it with cerebro.addstrategy or cerebro.add_signal?
I tried both but can't manage to make it work...
Thanks for your help!