Attaching purlin wall to steel

I'm in the process of the worlds slowest loft conversion (Getting things done in my own time as and when time money allows).

BC have been notified, all above board.

So far as I can tell, there are 2 ways of connecting the purlin wall to the top of the steels.
1. pre-drill top of steel, place timber on steel, bolt down.
2. Hilti gun, shoot nail through timber into steel.

I built my purlin walls on to the steels, connecting them to the rafters, fully intending to go for the gun option after they were in place.

Just wanted to check, is this http://www.hss.com/index.php?g=52245#SpecificationTitle
the sort of gun I'm after?

And out of curiosity.. as opposed to the two options above. Could the timber not be strapped down to the steel? Using some steel band??

what width is the top of the steel and what is the width of the timber set on it?

The width of the steel is approx 8"
The width of the timber is approx 4"

Job done.

Hired a Spit P370.
5 minutes work.

Bit worried before using it (no experience). But a doddle as it turned out.