I agree with most of those points. I veg horizontally because I'm in no hurry to grow my plants - I have 8-10 weeks to clone and veg before putting each new plant into flower - and also because it saves a bit of height (which I don't really have in my veg/clone chamber). Also, it's easy to promote a bit of stretch by simply raising the lights. A bit of stretch can be a good thing in a vertical grow.
On the subject of cooling, I have an extractor fan hanging directly over my bulbs, with a floor fan blowing directly up. This is the best set-up, IMO.
Where I disagree, slightly, is in the use of the floor fan. I have mine blowing fairly hard, because the floor fan does two things: it ducts heat away from the bulbs, but it also blows through the plants to help strengthen the stems/branches and prevent mold. As long as you have a good extraction fan, you don't have to worry about hot air blowing all over the place: because the air is being continuously circulated, with cool air being drawn in and warmer air being sucked out.
The faster you suck out the warm air, the less time it has to heat up inside the grow chamber, so it really doesn't make much difference whether your floor fan is set to low or high - it is the ceiling fan that is extracting the heat. The floor fan merely ducts heat away from the bulbs to allow the plants to grow close without burning. Once the heat is ducted away from the bulbs, it dissipates within the grow chamber.
You do want a certain amount of warmth within your grow chamber, because plants respond to warmth and grow quicker than when it is cold.