Possible LO Deal

I have not completed a L/O yet and I am trying to figure out the purchase price for a property. Owners RV opinion $155000 My RV opinion from comps is $148000 Here are the details of my offer so far L/O to homeowner: $1000 down $1000 per mo for 36 mos I L/O to prospective buyer for: $2500 down $1500 per month My questions are what to do with the purchase price? Offer the $155,000 for the 36 mo period considering the homeowner will gain $8000 more equity on their orig mort plus $5400 ($150 per month) from my $1000 rent payment? or Offer a 3% (or other %) yearly increase to the price depending on when the option is exercised? The property also needs carpert and paint...that should come off the ultimate purchase price .....correct? Thanks!