lwip MicroC/OS-II throughput

When using LWIP + uCOS, I see there are quite a few tuning options available thru the GUI and in the file opt.h . What changes to these default options are you finding helps the performance? Is there better documentation (other than the code) to explain what some of these do?

I see that some are using a 10ms timer interval for uCos, despite using a fast clock. I believe the HW timer defaults to 1ms, so was there any performance testing done as a reason for the longer interval?

thanks