Not able (willing to spend time) to provide you with the text book stuff, but from a practical point of view I donīt see what stops you from doing an IFR flight, with and IFR departure, but with visual reference until 396ī(or 394ī..). If itīs a sh@t wx day, then wait for the improvement if youīre uncomfortable. Further to that, the perfomance data used for the terps or pans ops construction of the departure would certaily cater for larger commercial jets, with a much longer takeoff distance than most biz jets at average weight, so you climbing to 400ft before turning, seems like a reasonable safe choice as well. Anyways, just practical input, not contributing with text book references, sorry.