How can you earn more to save more? 

I think you're missing a key ingredient: how much time do you have to earn your 20%?

Conventional is always going to be the cheapest, but sometimes it doesn't work due to a buyer's financial situation or their desire to keep a property out of their personal name. 

creative financing gives you the opportunity to earn income via interest.

In an ideal situation, this kind of deal can benefit all the parties involved, especially if it's a highly desirable property; The seller gets some privacy, the agent makes a few calls, and the buyer has less competition.

If your properties are located in city with SB 721 enforcement mechanisms in place, I would contact the city for inspection guidelines and then find an inspector and contractor who understand those guidelines.At the risk of sounding undiplomatic, I have zero desire to pay someone $4K to drill holes in my balconies.

As long as your investment is in a neighborhood with high demand for rentals and is a desirable area, it should meet your expectations.

If you want to brush up on PML, I suggest you check out my book Lend to Live: Earn Hassle-free, Passive Income in Real Estate with Private Money Lending available on the BiggerPockets book store.

Here is my situation:- I'm a W2 employee that earns north of $500k a year- My wife is a stay-at-home-spouse- I'm looking to buy ~ $1,000,000 in STR Real Estate by the end of the year (as an investment and to offset my tax bill)I'm fairly well versed in the rules surrounding using STR to offset active income.

First just want to state, she is your girlfriend not your wife, which is very different in regards to financial status/situation.For me its simple, I am buying this asset and taking on the risk of renovating it and as part of it will be seeking to earn income from it to better myself in the future as I know a W2 job and a 401k does not get you far in retirement.