I guess you are referring to the "False Stem" - ie the one which will remain visible, as opposed to the actual (plywood) stem which will be hidden inside the structure when the strakes (planks) are fitted.
We used "Utile", and to the specified dimensions. It would have been best to just bond one at a time (obviously two for the first bonding!) clamping to the actual (plywood) stem to get the shape.
We actually bonded all the false stem laminates in one hit. It was a bad move. The lubricating effect of the epoxy meant that the laminates did not want to stay lined up.
I cant comment on the bending habits of sapele. Could you try bending a scrap bit without steaming?
If it really does need steaming, I'm sorry I can't help.
Good luck, take your time, enjoy the process.
(NB mine is not the definitive opinion.)
I do mean the false stem. I just kept the title short as
I wasn't sure if everything would fit in the Title box.
There has been no response to my request to date so
I might try the tea-towel and kettle malarky again.
I built mine from the kit so my outer stem is ply. I've never steamed, but I've read that a steam wallpaper stripper attached to a length of drainpipe vented at the other end is the way to go. 20 mins for green oak, I don't know about other species.
I live in Rownhams and sail in Chichester Harbour.