Banks require a minimum 6 months reserves for these products and it's a good guideline.  

Less leverage means that the greater cash flow can more easily cover unexpected expenses without di[ping into capital reserves or personal cash, hence less stress.  

For instance, for any reservations with VRBO and some 3rd party or direct book reservations, they use their own cc processing which has high fees. 

I would really focus on raising capital so you have enough reserves to mediate risk.

I would want to keep extra for reserves along with contingencies, plus if anyone in the area has stored away the 10,000 for a cost segregation details on that would be helpful too.

The bank reserves the right to call a mortgage due upon a sale. 

However, you need to have 6 months of reserves and its 25% downpayment for commercial loans.

US 10 year Treasury yields tumbled (by nearly 10 basis points today and counting..) with the latest inflation metrics showing a dip last month indicating the Federal Reserve could start to lower interest rates this year with a now 80% chance of a September rate cut. 

I have enough put away to purchase a few properties for rentals and kick start everything with a faster scale and keeping reserves on hand.

If 10% is sufficient, do that and keep the remaining money as a reserve or for your next investment.