Insulation, Radiant and Vapor Barriers - Hip roof venting?

Firstly, thanks for all the help on my project to date.

I have a question concerning hip roofs, insulation and venting.

We have a garage we are converting. It has a hip roof and I have insulated it well (floor, walls, new windows, etc.) and am about to tackle the ceiling. I am adding a couple of skylights and keeping an open ceiling by insulating between the rafters.

The building is 300 sq feet and will be heated by natural gas (to about 60 max). We live in a cold, dry climate.

My question: what is the best form of venting and where would the vents be? I understand the principle of venting in a space above an insulated ceiling but when the rafters are insulated and there is no space?

Any advice much appreciated.

I think you would be better off to put a ceiling in there and insulation on that. You roof will last a lot longer. Put some button vents near the ridge.
I am adding a couple of skylights. You can box them down to the ceiling.

There is a foam you could try.

ED;)

You can get u-shaped foam spacers that install between the rafters. These provide a continuous "tunnel" airspace between the roof deck and your insulation layer. Usually you would put in soffit vents and a ridge vent or button vents as previously mentioned.

Also you can consider icynene foam which in most jurisdictions requires no venting and does not require a vapor barrier. But it is relatively expensive and must be professionally installed.