Is this even a viable proposition?

Then you can test different headlines, unique selling propositions and creative copywriting.Mailing 31 pieces?

The first is marketing you unique proposition, the second is a little more dicey. 

Ok, I know this relates to an entirely different country  but the USA also has legislation governing unfair terms in consumer contracts and they probably entail similar legal doctrines.Basically the proposition is this.

From a fellow Californian: God save Proposition 13.

That may well prove to be a more fruitful proposition than trying to sell a house with an uncooperative tenant, and dog hair.

Supplementing any tenants rent is a losing proposition that hobby landlords mistakenly believe is a benefit in retaining tenants but in fact has zero relationship to how long a tenant will stay.

Taxes are based on the transfer price of a property upon sale and under proposition 13, reassessments are capped at 2% annually.

Pursuing  collections is court is a losing proposition (collection companies buy this debts for pennies on the dollar for a reason). 

These are the questions you have to address and they calculate your cost to value proposition (including time and energy you invest).