Hard Starting Cold Continental Engines

My Seneca V (Continental TSIO-360-RB) has been very hard to start
during cold weather for the past few winters I have owned it. Besides
burning out several starters I have tried tune-ups prior to winter and
installing the Slick Shower of Sparks ignition system. All have helped
a little but no dramatic improvements. My mechanic has been researching
this issue (he also has another Seneca V o nthe field with similar
problems) and has come up with a somewhat obscure Continental Service
Instruction Letter that references cold weather starting and discusses
New Cylinder/Induction Port Drain Connections. This involves 24 new
drains ($200 ea.) and before I make an investment on such a vague SIL I
thought I would seek others experience. Is anyone familiar with this
and care to share experience?