Sometimes the arbitrage window is very small....
It won't ever be quite that quick. There's a limit of one call per minute to that API and it's also cached. Would guess average time for transfers will be 2-3 minutes once it's all running - which will hopefully be by the weekend.
Have been ironing out some glitches today (more testing to go) then tomorrow will be running it in test mode where it'll report transfers and what it would have done but not actually do it (that'll speed up transfers anyway as I'll see more promptly when I need to do some). If that works fine tomorrow then on Saturday will probably turn it on for smaller transfers (under 100) and do large ones manually then let it go fully live once I've checked all the safeguards are working properly.
I didn't develop it - someone else did (up to them if they want to take credit in public or not).