I made that crosshair by my own with Photoshop and TXDworkshop:
Go to your GTA SA folder > models > hud.txd, copy that to somewhere and open it with TXDworkshop.
When you did that you need to klick on the 4
th image (siteM16), press on the Export button and sellect PNG and save it somewhere.
Open Photoshop (Don't close TXDworkshop) and edit siteM16.png, when you're done: save the image and close Photoshop and go back to TXDworkshop.
Press the Import button and go to your edited siteM16.png, then press "Save TXD".
Now the last step: Close TXDworkshop and copy the edited hud.txd to the location in the first stap (GTA SA/models/hud.txd)
BTW I think that my English has been improved again.
@David_GER: Whoops, edited