Tyre Wear

Is there a way of getting an estimted tyre wear per lap from your test runs or anything like that? Or is it just guess work?

These test runs are only to help you to make a setup, but give you no data about wear, fuel consumption, tire temperature, don’t help you about push settings,… .
 
But the second season you will come to a race, you can look up the past races and calculate the tire wear and fuel usage. Still you are not able to see the push settings (which has influence on tire temp, wear and fuel consumption), but if you remember them it helps. But don’t forget the weather and temperature, this has a lot influence on how the tires behave and so in push settings and even in the choice of hard and soft. Number of pit stops are dictated by the tire choice and push setting you use.
 
In other words only the experience (and making notes) can help you to estimate tire wear, fuel consumption, right push settings, strategy,…. .
I wish the Dev’s would give us the tools for this.  

i just started playing in the last week and it seems very shot in the dark. Better data from test runs would help...

It is a management game - you are meant to keep your own info and work things out.
Some of the mods have made spreadsheets that you can use.

*shouts for help from the devs*

I gather the test run data will be implimented soon
And just to make things clear - I have never kept data and 'play in the dark' the whole time!!