When I say large I mean $250mill projects +.

I agree with @Don Konipol, if the overall cash on cash return for this project is only 10%, it's not a viable deal.

Should I open a separate HYSA or similar vehicle to park additional cash reserves and or taxes set aside from prior projects?

Some land flippers will buy unwanted and neglected parcels of raw land for a bargain and then improve them by clearing the land or even leveling it before selling it on.Most land flippers are making money by actively seeking and marketing their land flip projects.

Naturally my biggest hurdle is the capital to fund the projects.

Every project is way different, too many moving parts in this business....

Projects can also take a lot longer, and cost a lot more money, which can have a significant impact on your bottom line.

I use term policy and invest the difference to fund a whole bunch of projects, too.

Based on those numbers for a small project, I would say that's not too far off. 

Your lender will ask "how many completed rehab projects have you completed in the last 3-years?".