We've just released an update to the Fit Calculator App (available for Apple and Android) to include a Bike Length projection for Tri bikes. This screen has also been redesigned to make it easier to interpret the numbers depending on the bike type, which is defined by the handlebar style, noted in (...)
Remember these projections are for recommending a bike size, and for establishing an initial fit position for a rider. They are not meant to prescribe a final fit position.
If you don't have the App, and are using the slide chart, you can calculate the tri bike length (top tube + stem) by using the road bike numbers and subtracting 2cm.
Note that the App factors in the Soft Score, whereas you have to do this manually with the Slide Chart. You can download the latest version of the Fit Kit worksheet for use with the Slide Chart