These are the two gas lens setups I use:
The Pyrex nozzle is a little fat for inside corners at times, the Alumina nozzle looks fat but the taper allows it to get into corners without excessive tungsten stick-out.
I switched to the Alumina lens and haven't went back to the Pyrex, I need to put the Pyrex back on and see what my impressions are with a little more experience under my belt.