Hey @Bryan Wilson I think this is a good discussion, and one that is definitely beneficial to new investors who ask me this question pretty regularly. As a full-time agent and an investor who has worked through the crazy market swings of the last 10 years, here are my thoughts.
There are multiple layers to answer your question, but the short answer would be that I agree with those that say you should just get your license if you want to take the "100's of offers" approach. If you want to make fewer higher percentage offers, find an experienced investor agent, tighten your analysis and approach to offers, listen to their advice, and let them do the hard work.
In Colorado, you can get licensed and up and running for around $1500, and the cost to maintain your license would be less than $1K/year for what you want to do. You can hang your license at a discount brokerage that just charges a couple hundred bucks per transaction, and they really don't care what you do beyond that, so you don't have to worry about any time commitment that would take you away from your other pursuits. You also can leverage your buying-side commission for discounts, or take the commission and apply it towards your costs, which would offset the cost of getting and maintaining your license pretty quickly. You can definitely work through the listing agents, which will work for a little while, but this town is smaller than you think and they will pretty quickly stop working with you on that front because it is a time waste. It could be a good bridge until you get your own license though.
The bigger question is how effective the "spray and pray" approach to offers is...answer: it's somewhat market dependent, but for the most part it's a waste of yours and everyone else's time. I will go out on a limb and say that almost every experienced full-time investor will tell you that vetting a large number of properties and making strong, targeted, high percentage offers on the top prospects will net you far more quality properties in the long run (and the short run too, come to think of it). I agree 100% that, as you said, you should not compromise on your numbers, which is why vetting 100 properties, then making strong (ie, not a prayerful lowball) offers on the top 4 or 5 will be much more effective.
In a down market, the spray and pray approach can be somewhat effective because you have a large crop of desperate or motivated sellers. In the current Colorado market climate (insanely hot) it will be totally ineffective because there is too much clutter and competition, and for open market properties with any potential at all there is fierce competition. Any potentially investable open-market property here will have 3-10 offers within the first 48 hours.
Sellers and selling agents look for two main things when choosing an offer: Who has the strongest offer (not necessarily the highest) and who is most likely to close easily and with the least amount of hassle along the way. A good agent will sell you and your offer to the listing agent effectively, and most good investor agents are known as such by the listing agents, and carry a lot of weight that things will get done smoothly and professionally. For many of the deals I get, we are not the highest offer...often not even in the top two, but skill and relational equity bridge the gap. In the Colorado market, knowing how to structure and sell an offer for maximum impact is really the difference between success and failure.
This is something you will never have with a green agent who has the time and willingness to write 100's of 1% offers...hence, both your time and theirs is completely wasted.
I know this doesn't answer your question about how to convince an agent to do all that work for you with little chance of return on their time, but hopefully it gives a little more context to all the answers above that say in one way or another, it's probably not the best route for you to take anyway.