) Well, when I locked at Datasheets and prices of MOSFET's, then I found that MOSFET for 5A good inaf... But I don't know exactly how much it must be...
BTW: How I can meashure inductance with ossciloscope? Ihave some old one...
3. With timings I haven'tt any problems I think, because, between switching +/- I have about 0.4 sec. MCU must give this secuence: 0.8 sec - (one direction), 0.4 sec - Hi-Z, 0.8 sec - (reverse direction), 0.4 sec - Hi-Z and so on...
I don't think you need to measure the inductance since, as you said in the quote, the current is off for 0.4 sec, so that should be long enough for the coil energy to dissipate.