What are the best iPhone settings for accuracy while bicycling?

[whogastim]

I use Trails on my iPhone to record my bicycle rides (10+ miles each)
on streets and paved trails in Chicago. When I upload to TrailRunner,
I often find that corners are cutoff and my distance is
inaccurate.

Usage: I start the application and then put my iPhone in my
saddlebag. I do not use the iPhone map function while I ride so I
disabled Live Map and Controls to improve battery life. My settings
are:

Accuracy is set to 200 yds.
Distance Filter is off
Live Map Enabled is off.
Controls Enabled is off

In order to improve accuracy, should I reduce to a very low setting
(20 yds few waypoints) or very high setting (2000 yds, many
waypoints)?

Should I also enable Distance Filter and set it to a very low minimum
distance?

Thanks for your suggestions

Tim