I want to pick up a tool for installing GXP bottom brackets, which have external bearings and require a tool with 44 mm od and 16 splines. The same tools reportedly work for many Shimano external bottom brackets and other brands.

Park Tool makes the BBT-9 and the BBT-19.2. The difference is that the 19.2 is a cup-type tool that allows the use of a torque wrench, while the BBT-9 is an open ring that doesn't take a torque wrench. I have read in several places that the cup-type tools tend to slip off BB bracket easily, marring it and potentially damaging the notches. (The SRAM/Truvative version of the tool reportedly has the same issue). I would prefer not to do that, but as a home mechanic, my arm might not be well-enough calibrated to get the torque into the right ballpark just by feel.

Here are links to the tools:

Bottom Bracket Tool - Park Tool

Bottom Bracket Tool - Park Tool

I can probably get someone to help hold the bike while I'm torquing the BB, so I can concentrate on holding the tool in place, but it would be nice not to worry about it in the first place.

Any tips or thoughts on this? Maybe slipping isn't that much of an issue, or maybe I can just crank it down tight with the other tool and not worry about getting the torque perfect?