fiistay, vaporizing allows for a generally more cerebral experience, whether you use a indica or a sativa, and on top of that, the extraction is more efficient than combusting.
Plus, there are some sedative cannabinoids missing that boil at temperatures higher then the point of combustion, and there is less THC oxidation, which also means less sedatives.
If you do 5 bowls in 30min, depending on your tolerance, there is the potential to over shoot it and pass over to the unpleasant side of cannabis.
Cannabis is relatively harmless, if one knows how to use it. I would follow the advice of NaturalFarmer, do a hit every 10min. And if you do a bowl real quick, wait at least 15min to see where you at, before doing another.
With vaporizing the onset is slightly delayed but it maintains the high for longer.
I have overdone it in Am'dam, after one hash joint too many but nothing major just a little anxiety and sugar crash. Went to the bathroom and splashed some water on my face. I had already ordered a hot chocolate so the sugar crash was dealt with.
I also overdid it when i drank a cannabis milkshake, called bhang lassi, in India. I couldn't sleep, was way too high, very anxious and it felt like it took ages for me to normalize and i remember i was thinking wheter it would make me crazy.
I took a shower and laid down and after a while it subsided but i was exhausted by now and slept like a log. This took like one hour. With eating it is a little more powerfull than either vaping or burning.