The memory limit is because Zorro is 32-bit. oP Group is working on adding a 64-bit version, as noted here:
Features planned for the next releases:
Overcoming the 32-bit limit for training and backtests (Zorro S; in development).
This is great news. Still, would be great if developers enhance possibilities of .t1 by adding additional volume fields and making an option for "order fill check" during the backtest.
