I think knowing more numbers, heloc limit, plans and objectives for future goals all should play into "what is best".

If you have mastered RE principles, assessing the value of the collateral is fairly easy. 

The principles would still be valid though 

With the increased competition, it’s also crucial to prepare your listing to stand out and work to address buyer objections prior to going on market.

Assets identified in this study include:Building Systems: plumbing, HVAC and electrical distributionInterior Construction: flooring, drywall partitions and ceilingsStructural Components: doors, roofing, windows and wallsPermanent Fixtures: emergency lighting, restroom fixtures and signageThis engineering-based cost segregation study included the following methodology:Physical Inspection through a site visitDocumentation review including architectural plans, accounting records and construction documentsA cost analysis which utilizes engineering principles in order to allocate costs to their applicable asset classificationsCalculation of the depreciation schedule using MACRSAs a reminder, bonus depreciation started to phase out in 2023.

My objective is to establish my network in the region prior to my arrival.

Once you read the explanation below, you will understand how REALLY bad things can be if you don't get the letters but go through with the purchase.First, the owner/seller should have a clause in the lease requiring tenants to sign (or object to in writing) tenant estoppel letters if presented to them.

I paid both sides of closing costs. 100% seller finance, 5% interest, amortized over 23 years, with a balloon payment of the principle balance due after 30 months.

6.125% has P&I of $2625/month.5.75% has a P&I of $2521/monthThis is a $104 benefit.Paying $4400 more towards principle will reduce your payment to $2598, a $27/month savings.Math says buying the rate down has a larger net benefit to you up front, but it will take you 42 months to break even.

@Michael Camacci, KP is Key Principle.