Persistence and consistence.

Ideally, I'd like to take advantage at Airbnb'ing both units, but I am wondering if I should play it safe and long term the top unit to ensure consistent income and Airbnb the bottom unit.

Whatever you choose, you need to be consistent with your marketing plan. 

So you invest wisely and consistently.

My current portfolio mostly consists of duplexes and triplexes in the Greater Boston area.

If there aren't comps there I personally would value the property relative to its potential rental income using either the gross rent multiplier or cap rate method. 

If you stay consistent, however, the business will begin to grow. 

But you want to make sure that they are predictable and consistent, because that's a direct reflection on what you can expect to get from them in the work place.Get everything in writing and communicate expectations clearly People can't read minds.

So they go get a money order and deposit it.All it takes is training... train your tenants and be consistent.

There is an odd thing about listing STR's (I just listed another one) in that it takes a while to rent consistently.