Use any JASO-MA or MA2 or SAE SF-SG oil of W 15-40 for this bike.
motul is one of the best synthetics on the market imho I use it in my shadow 750
Under the rear of the engine.
The oil capacity for vt750 is 2.4 quarts
if i am not mistaken a late model 750 dc shadow holds 2.5 quarts with filter change
any brand that is 29/50 in weight
For the Honda Shadow VT600C, you need 2.1 liters for an oil change and 2.3 liters if you also change the oil filter. For the VT 750 Shadow, you need 2.4 liters, 2.6 if you change the filter. For the VT1100 Shadow Spirit you need 3.1 liters and 3.3 if you replace the filter.
SAE 10w-40 API SF or SG oil. I would recommend you use synthetic.
15410-MFJ-D01 and that's D(zero)1