Yep this should do it.
You can check out Q3Map2Toolz as well. I use it to compile my maps.
There's a nice and easy to understand "how to" here:
http://www.inficad.com/~mnichol/dummies/index
Note that the link to q3map2 soesn't work anymore since shaderlab is no more

But you can point q3map2toolz just to the q3map2.exe that you already have.
For sharp shadows try key: _lightmapscale value:0.5 / 0.25 / 0.125
in your worldspawn-entity. For additional info see the information of your worldspawn entity (worldspawn = everything that's not a special entity. Like a simple brush). To see the information just select a brush and press "N".
Note: The smaller the _lightmapscale, the sharper the shadows are. Sharper shadows = longer compile time = larger bsp.
There's also a workaround if you only want sharp shadows in specific places.
This can be useful if you have a large map and/or compile times get too long due to the _lightmapscale in worldpawn.
func_group the brushes where you want sharp shadows on, and set the _lightmapscale for this func_group entity only. This results in sharp shadows on this func_group.
With using the following switches for your -light stage, the overall compile should be optimal.
-light -fast -deluxe -bounce 3 -filter -patchshadows -samples 2
Hope this helps