I agree with this.
If you want that classic Harley lope, you better get a Harley with a carb then - aint no way you're doing that with FI.
And I think even H-D recommends no lower than 850-900 to maintain correct oil pressure...

 

I keep my carbed EVO at around 700. Been doing it for years with no problems. When it is hot the oil pressure is very low or none at all, but plenty of volume flowing through the engine. With roller bearings on the rods and crank, you do not need much oil, and at idle there is no load on the engine. If oil is moving through the engine all is good. If you take out the timing plug while it is idleing, you will see there is plenty of oil flying around in the case. Just my 2 cents, and Twin Cams maybe different.

 

Twin cams use oil for cooling the heads ... Low RPM is not enough oil to cool them down = fried valves. Thanks to EPA twin cams run way hotter than EVOs