I use "DU Meter" which is a bandwidth meter running off of PC. The app measures the download and upload throughput and provides hourly loads as well as stopwatch functionality to measure user defined intervals.
Of course, in order for this to accurately measure the DNS-343's true transfer speed, everything on my network (router, cabling, PC network card) must be faster than the DNS-343 to ensure there are no other bottlenecks. Anyway, I use this app to measure the hourly download rate, which I then extrapolate to estimate the completion time for large file transfer jobs.