How to increase length of whiskers of "standard, static" crosshair?
Solution 1:
http://www.krisskarbo.com/csgocrosshair/
This is a crosshair generator. Tweak whatever you need and then save the Config it gives you. Pretty self explanatory.
Solution 2:
cl_crosshairsize
Play around with the numbers to figure out what size works for you. I typically prefer a small crosshair and use 2. If you want longer, you should try something like 5 or 6.
You can also adjust the gap in between the crosshair if you don't like how spread out or close together they are with the following (I like it close with -2)
cl_crosshairgap