Does anyone know how far should a commercial jet (787,777,etc...) be away from each other in runway or in process of taking off?
Are there public resources that I can look up?
There are a wide variety of cases to consider on the ground and during departure but you can find a lot of the regulations/guidelines in this document.
For example here is the case for wake turbulance seperation,
- Separate a small aircraft weighing 12,500 lbs. or less taking off from an intersection on the same runway (same or opposite direction takeoff) behind a departing small aircraft weighing more than 12,500 lbs. by ensuring that the aircraft does not start takeoff roll until at least 3 minutes after the preceding aircraft has taken off.
- Separate a small aircraft taking off from an intersection on the same runway (same or opposite direction takeoff) behind a departing large aircraft (except B757) by ensuring that the aircraft does not start takeoff roll until at least 3 minutes after the preceding aircraft has taken off.
That is just one example, the document is very lengthy and covers a lot of cases, you should be able to find what you are looking for. You should also keep in mind that things like weather and local airport policies will cause the regulations to vary a bit. For example a local noise abatement may cause the seperation/interval timing to be larger than required to adhear to the noise abatement.
That covers mostly what ATC will see and do, you can take a look at this document for how pilots look at departure procedures.