Joe,
In response to your questions...
"...Right now I have Zen-Ray ED2 8x43 binos. Do I also need a spotting scope for spot and stalk hunting? Or
will my binos do?"
I'd say go with what you have. Especially if you are on a budget. Fancy gear doesn't kill bucks, the knowledgeable hunter does. Most of the old timers laugh at us nowadays. Before Cabella's and Bass Pro Shops catalogs were around they were killing plenty of deer in this county with Sears binoculars, plaid shirts (colored red and black), stick bows and iron sites. The key is to get out there and keep the wind in your face. Try not to get hung up on the gear. You know we have a name for people who do?
Don't get me wrong, I love my hunting toys. They do enhance my ability to kill critters but I am surprised how often my kids and I kill game that didn't involve the use of anything but the basics (boots, bow/gun and a knife.)
I am not familiar with your binos but they sound like they'll do. San Diego Co. is big country to glass. When it comes to binos I like 10x42 or 10x50 power. I am partial to Leica because they are crystal clear at distances over 1,000 yards and they rarely fog up. I do use 8x30 Nikon's when I'm stand hunting. Alpen's are also good for a lot less $$$$.
Having a spotting scope saves on the hiking time and allows you to count antler points from great distances so you don't spook deer. I'm getting older so this is a big deal for me.
Good luck!