Question about BG levels

Spikes are all different one from another. The only official advice is that it should be below 8.5 after two hours. Having said that there is no guarantee that it is not still going up due to eating low GI food or protein. If you want to go to such lengths you could take a few readings and plot the spike to see if it's early or late and when the peak is.

As to the last part of your question, yes a person's metabolism will affect it and so will the food that you eat since all foods are absorbed at different rates into the body.

Sorry to say it isn't simple. It will vary on the type of food, the amount, even the time of day.. and what combination you eat.
You will have to test and see what happens to you.
For me, adding fat will turn a sharp spike into a gentler curve. Berries are negligible if I have them with double cream.

generally the peak of your blood sugar high is likely to be round 45 minutes after you begin eating At 90 minutes you should be back to being low again - normal non diabetic would be under 6.7 at that stage . For many of us its easier to acheive that in the evening rather than the morning .

I think you would need to test and see when your spike occurs. I've only tried testing after evening meal and for me it was highest at 60 mins and going down at 90 and down more at 120. Though I haven't tested enough different foods to be sure this is always the case for me. I think there are too many variables that can also interfere with this such as exercise, stress and illness each of which will have an effect.

If I'm trying something new or that I haven't had for a while I test at 1 and 2 hours.

As others have said, there are too many variables to give a definitive answer.

The most important is your own personal insulin response - whether you have a depleted first response, a reasonable first response, a depleted or reasonable second response, plus how much insulin resistance you have. Then there is the combination of foods eaten.

My personal peaks are between 60 and 90 minutes. Then I start to come down. (my Libre sensor confirms this). Depending on what I have eaten I am usually back to normal between 2 hours and 2 and a half hours.