Which option affect the final size of orthophoto, and speed

[Samdrone]

I only need orthophoto.
Sometime, for 1 30 Acre orchard, I fly around 230-400 images with 20MP. If I choose full resolution and ultra, ultra computer option. It run around 9-10 hours. And the orthophoto is around 1 GB, GSD is 0.85inch.

I usually run another for small size for share. The small orthophoto is around 200MB, GSD is 2 inch.

And my question is , which option in webOdm affect the orthophoto size and speed withou affecting the quality of image?

I can skip 3D, set GSD(orthophoto-resolution (float > 0.0) ) higher,
but how about
feature-quality ?
pc-quality ?
resize-to (integer) ? This is very confusing option for me.
resize-to (integer)
Legacy option (use --feature-quality instead). Should I check this, if it not affect the resolution quality?
Resizes images by the largest side for feature extraction purposes only. Set to -1 to disable. This does not affect the final orthophoto resolution quality and will not resize the original images. Default: 2048

And last question, if these options are set, can I save this option with a config file, next time, I just run it as a option?

Thank you for your help.

[pierotofy]

Try sfm-algorithm: planar. If your scene is flat, it should be much faster.

[Samdrone]

Thank you. I just figure it out I can change resolution and run from orthophoto, only take 1 minute.
Mission completed.

[Samdrone]

thank you very much. I use planar, and 20 gsd, only took 43 minutes to finished. amazing