Maer I have 2 small tents and run the same set up in both....A 150w HPS with 4 23" T5's at the corners.....gives me over 9,000 lumens per foot.
The T5's are 2000 lumen each and are often times touching some of the side branches.....Never had a problem with it but with good ventilation I keep my temps in around 78 with the lights on.
Most of the time the T5's are within inches of the girls....They just don't get that hot and they do have a clear cover over the bulbs.
One thing I have noticed with the side lights is that I don't have to trim as much of the smaller branches and buds...If I spin the plants about 90 degrees every morning they seem to love the extra light coming directly from the sides and rarely do I get yellowing on the lower leaves.....and my "popcorn" buds can pack on some good weight.
peace....