To intentionally reduce the leverage more than required is a foreign concept to me especially in the San Diego market.  

This requires a dedicated effort sourcing and analyzing hundreds of deals to find the one or two worth pursuing.  

Lenders desperately need/want business especially in this interest rate environment (right now, the main source of mortgage loan business in Florida is rehab financing as a result of the hurricane damages) and one way the big players differentiate themselves is by streamlining the process.

And i found launch control but the minimum is $500 a month, but they use cross-referencing data across sources to find the most accurate contact information by using a person's name and address to find their phone number, real address and email by accessing public databases, phone number directories, credit reports, utility bils, public tax records, and social media profiles. this is waaay expensive for me as a beginner. what do you suggest or if anyone has any suggestion I'd greatly appreciate it.??

The good thing about CA, is once you do source a deal, you are pretty much set.

Sources of investment propertys and yhield based upon a buy and hold strategy,I hope you can help me.Wow,Its been a while since I have been back home haha2+ years now lolIts too expensive IMO and many folks are buying high and hoping to sell higher.Hoping a property will go up in value is not a strategy.

However, seeing as though I have already sourced the deal myself, would it still be in my best interest to use a realtor for this transaction if it works out? 

Like others have said, you need to find alternative lead sources to find a decent deal.

Without the high leverage you reduce the top source of return in CA RE which is achieve via the appreciation on a high leverage property.  

I recommend researching the average appreciation over the past 10 years in your target area to get a clearer picture.As you know, in real estate, ROI comes from multiple sources: Home Appreciation:  Reno Appreciation: Value added through renovations or improvements (usually just in the first year).