Interested in all cash financing but don't know where to start!

[Weston Link]

Hey everybody, I am fairly new to Bigger Pockets but have absolutely loved the community and resources here so far! I currently bridge the gap for investors who are interested in buying real estate but don't have the time or knowledge to pursue it. We work together to come up with a budget and then I invest their money in assets that fit their desired criteria and I absolutely love it! Sometimes they leave the entire process up to me to decide how and where to invest their money and although it can be stressful at times, it's honestly a load of fun.  It's almost like getting a paid scholarship to RE Investing University. I learn something new about investing all the time and that pushes me to learn even more. In the past few weeks, I have been thinking about doing some larger deals. I would like to buy a large storage unit facility and an all cash offer would be ideal for getting it at the right price. However, I would need between 250-275k in cash to facilitate the sale and the majority of the investors I work with just don't have that kind of cash available. After running preliminary numbers on the property, I believe I could guarantee a 7-8% return for a cash lender and would still keep roughly 10k annually for myself to run the facility along with online support staff who work specifically in the storage unit industry.  

How do I go about finding cash lenders besides local word of mouth and networking?

What %ROI would be considered acceptable to an all cash lender?

Finally, how do I go about convincing a lender that the business model is safe and profitable? 

Any advice would be greatly appreciated on this topic and thank you in advance for your input!