Rotisserie temperatures?

[Tigermad]

Got myself a cracking new gas bbq last weekend. It has a rear infrared burner for rotisserie cooking. Put a 6lb chicken on it to try and to my surprise the temperature would not get any higher than 300 degrees (approx 150 c) and that was on high heat. Looking at the internet I read the best temperature would be about 350 degrees. Anyhoo because of the lower temperature I left it in half an hour or so longer and it was tasty but a little bit dry. Also I put some par boiled veggies under the bird for 40 minutes to catch the drippings but again because of the lower heat they didn't crisp up how I would have liked. Should I have just left them in for the same time as the bird (around 2 and half hours)?

A few people have said I can put one of the main 3 burners on low to get the temperature to rise a bit but my instructions say not to do this (because of flare ups etc). But if I have the drip pan underneath then there won't be any flare ups will there?

Do most infrared rotisseries only get to around 150 degrees centigrade?