This is very individual. My suggestion if you want to know for sure is to buy a glucometer and experiment with timing, amount and type of carb.

Metabolically healthy people and those who are very active can get away with more. Timing still varies though. There are a growing number of high endurance athletes who are keto and do so with more than 100 g of carbs a day because of activity level.

Zach Bitter is one who has his own blog if you want to check it out.

As a former CKD/TKD user, I can say for certain that it does. Hell, just have a look at ketogains on reddit, and you'll see all kinds of anecdotes of people having better training with pre-workout carbohydrate. The body tries to burn off excess glucose first, assuming healthy metabolic function.

It's why I absolutely could not sit still during my carb refeed days, if I overdid it. As soon as my glycogen is restored, my system hits "okay *kitten*, tank's full, time to burn something" mode.