For harvesting canola, the Canola Council of Canada (CCC) explains that because the characteristics of a standing crop can be distinctly different from that of a windrowed crop, combine settings may be quite different in each situation. The cleaning system may be the limiting factor in maximizing oilseed harvest for a dry, swathed crop for example, but the rotor is more likely to be the limiting factor in a straight cut crop.
In general, for straight cut, ensure your reel height is not set too low or substantial loss will result. CCC advises starting with the same settings you use for swathed canola and then fine-tune from there. Also remember that green canola straw can use up combine power and overload the shoe if over-threshed. In a lodged field, travel perpendicular to the crop lean to facilitate better pickup in both travel directions.
For a harvest management and troubleshooting tips visit: https://www.canolacouncil.org/canola-encyclopedia/harvest-management/