While no one can deny that  saving even a a few fractions of a percentage in interest rates is a good thing, what most people end up doing is prolonging the time they carry such debt, and thus paying more interests in the long term, which I guess is a good thing for people in the lending industry.

It allowed me to offer a higher price to a buyer which put me ahead of the competition.

Here are some ways you might be able to achieve that kind of return:Find a property for a fraction of what it's worth (marketing to motivated sellers, nonconventional transactions).Find a secondary market that isn't hot, or is maybe even a little depressed (not Austin or Dallas).Become a slum lord - but most of us know how that turns out, and you even say you're looking for quality renters.Finding something that's easy to sell, easy to rent with a quality renter, and has 10 - 15% cash-on-cash returns - you're going to have to be willing to do a lot of marketing/networking to find that.

Even if I don't end up saving money vs. the original offer, probably doesn't hurt to "practice" being aggressive in finding competitive financing...

I am near Irvine all the time.If you find 60%-70% of ARV in SoCal, you would be a rock star ... you are in a much more competitive market than most, and Real Estate is highly localized. 70%-80% and you should be ok for wholesaling here ... if you can get it for less, all the better, but it would be very tough. 

The market is competitive.

Depending where you go you can find competitive rent rates (1brd apt will run you 950-1300) but you can also find some properties which will increase in equity nicely and will be able to cash flow for you when you move back.  

I imagine I would ideally want to price them a bit below market average to beat out some of the competition.

I'm as busy as I want to be but spring/summer tends to get pretty competitive every year.

A high income earner with a full time job and 30 out of state rentals isn't going to spend however many hours preparing his/her return and planning when I could do the return in a fraction of the time.