All the PX-10s I've worked on had 118mm BBs - as well as the PR-10L I had, which would have used the mod. 49s. My '73 PX-10E has very little clearance between left arm and cup, but it doesn't rub and seems to work fine.
I have in my possession a Phil BB unit that was used for many years with a Stronglight mod. 99, and it is a 119mm spindle.
My memory is that 113mm was for single rings; 118 for doubles; 123mm for triples.
Russ Fitzgerald
Greenwood SC
rfitzger@emeraldis.com