TWO flash units is NOT enough for a home studio for either people, or products, or for lighting rooms; you want to have MORE lights, like 4 x 150 Watt-seconds, or 3 x 150 Watt-seconds + 1 x 300 Watt-seconds, or something similar to this.
For most home studio uses, 200 Watt-seconds is plenty for your main light, half that for a fill light, 24 Watt-seconds for a hair light, and anywhere from 10 to 200 Watt-second on the background from one light unit.
With most modern studio type flash units, 300 Watt-seconds is actually TOO MUCH power for a huge number of situations. If your flash is too powerful to start with at Full, it really hurts your flexibility when you get down to 1/4 and 1/8 power levels.
It is however, handy in a 4- or 5-light setup to sometimes to have ONE light unit that is 2x more powerful than all the others.
If you shoot on GRAY seamless paper, and light the paper with two flashes at say 200-Watt Seconds, each, from metal reflectors, one light from each side at 45 degrees, you can "lift" gray paper to pure white background, and then shoot with 50- to 75 Watt-seconds on a main light and get that pure white background.
I would say buy 4 identical, moderate-power lights, not one 600 and one 300...I would rather own five, identical cheap lights. I think for beginners or hobby or light-duty uses, that expensive $400-$600 light units are not good investments: I want more accessories: 10,20,35 degree grids x 2 sets, barn doors, 2 of those, umbrella boxes, 2 of those, 1 BIG softbox, two 60x60 cm softboxes,and some stands, a boom arm,etc.. There are a number of really,really,really important SMALL light modifiers, like the honeycomb grids, barn door sets, and mylar or TuffSpun diffuser discs and gel filter holders that are much more important than the big octabox that most webbies desire so badly.