No! Nothing will ever work in your favour!
if the Boo has a slight twist but is V thin you will prob be ok. but don't expect anything to pull anything else sideways into line.
I learned a lesson with a boo backed Yew. There wasn't much Yew to play with and it didn't really line up right... but I clamped it all up...
It was fine for a few days then too a sideways bend... I tried all sorts of trick to correct the bend... they all worked for a few days or a week.
http://bowyersdiary.blogspot.co.uk/2015/03/the-returning-bend.htmlIn the end I sawed it in half
. Re-jigged it straight and made it into a take down
.
If it's wrong before glue up, it will be wrong after.
If it's right at glue up... it may still be wrong after. The way to be be safe is to have plenty of spare wood ... but we all know you can only work with what you have.
I'd say cut the backing strip dead straight ignoring any "grain" in the boo. Try top get it flat and evenly thin... may even be worth steaming it flat (but don't try to correct sideways bend)
All the above is only my best guess... can't beat careful preparation with any glue up. Others may have better advice to offer.
Del