KA 5-qt tilting time conversions from spiral

Hello all,

I'm going back through Hamelman, and in addition working through Calvel (and the Bread Builders).

I started many years ago and Hamelman was, and is, my bible.  Always got great results.  I'm trying out some scaled recipes from the Calvel book.  He uses spiral mixer for a given.  His pain au levain has a 5 min. mix/pre-autolyze, 30 min. autolyze, then a total of 12 minutes post-autolyze mixing on speed 1, which by his table gives 100 RPM for a total of 1200 revolutions.

One of two things.

Firstly, and I'm still trying to figure this out, Calvel has a short bulk ferment of 50 minutes, and a long proof of 4-5 hours.  If I pulled some relatively weak dough and had the time, I'd fold per Hamelman.  I've been trying one fold at 25 min. which lends some, but not enough strength.  I don't know if a fold after only 1/2 hr of bulk ferment does much. 

The other consideration is that I've never gone much past 8 min. for any mixing/kneading.  MY KA has a low speed of 40 rpm.  This Pain au Levain is a low and slow mix, so if keeping to speed 1, that's a total of 1200 revolutions or 1200/40 = 30 min. total mixing.

That seems crazy - isn't it?  Isn't there a concern about motor burnout going this long? 

The easy solution seems to go with the longer bulk and higher % preferment, as with Hamelman, and this affords a lighter machine mixing + fold(s) to get needed strength.  Before I do, though, I want to try to see and understand Calvel's approach.

Any thoughts?  Much appreciated.