Design width for Backed Yew bows?

[Easternarcher]

I have some yew lumber that I resawed as it was not suitable as staves.
I plan on backing it with hickory or maybe ash. Just not sure what width I can use for such a bow..66-68 in. length and looking for low 50's in weight.
I know Ipe can handle narrow designs(1 1/8th or 1 1/4th w)
English longbows can be done fairly narrow as well. Any suggestions?

[PEARL DRUMS]

I believe 1.25" would be fine for a max 28" draw. I would use hickory for your back.

[Easternarcher]

Thanks for the reply.

[Easternarcher]

Another question on this Yew I have. I see some purplish colored streaks. It kinda looks like where sap or resin has flowed into minor dects and healed over until I cut thru them.
Are these defects to be avoided? Reminds me of the reddish bark you see on the staves.

[Del the cat]

Any width you like... 
Yew is fine in ELB or thin flat styles.
Del

[Easternarcher]

Any width you like... 
Yew is fine in ELB or thin flat styles.
Del

So Del, do I need to be concerned with these purple streaks?

[Del the cat]

As you are backing it you will probably be fine.
Purple streaks are often ok, but sometimes a small branch or pin that has been cut off and grown over can be rotten and the overyling wood may show as a purple patch so if you can see one end of a knot but not the other look out for a purple mark indicating where it's grown over as a 'blind' knot.
This post shows the most extreme case I've met... but if you follow the blog you'll see I magaged to excavate and plug it.
http://bowyersdiary.blogspot.co.uk/2012/01/mystery-knot.html
Often it just shows where there was an adjacent knot or feature which has been lost when the stave was sawn out and the stave reduced.
It's amasing how many knots on the edge of a stave disappear as it's worked down... sometimes I take the trouble to plug 'em, only to find they have completely disappeared in the finished bow. I take a better safe than sorry approach to knots these days. Others just leave 'em very proud, all down to your own preference/experience.
The back is IMO the most critical, but you don't want any pockets of rot hidden in the belly which could collapse.
Del

[Easternarcher]

Del, I checked your blog and I will say that the streaks I see are NOTHING compared to what you have dealt with.LOL.
I think I won't worry too much...Thanks