Have you taken a look at the pedigree of my buck "Fort Knox" ? His anchor is pretty similar to your doe. I found someone who had a Grand Canyon/ W-8. It was like They were holding on to their inheritance into the promised land, lol!!!
You may want to wait and see how Texas Timber grows out this year. If he does what it looks like he will, I'd want a full brother or sister if I were you! It's a cross that's obviously worked very well for you.
Based on how Texas Timber looks I would either make sisters or I would use another buck that will put some TX in the fawn like Texas Tea did. Hybrid vigor and a little EHD resistance never hurt. Several Big and well bred TX bucks out there now that are worthy in the North.
Gladiator XL (Maxbo xL on Gladiator 2) 358@2 with a 230" typical frame
Express (Proven towork in the North out of Gladiator 2)330" plus and wide
Sudden Express (Express on Sudden Impact) 270-280@1?
Gladiator 2 (Look at the above bucks) Also Elite is a bigger full brother
Big Stitch or anything in that Stickers/Stitches line seems to work well
I know there are several well bred yearling also in the north that will put 1/8-1/4 TX in the fawns
I have a Slick/ Goldrush/ Hardcore/ Vortex buck fawn on the ground The vortex doe is blue 6 which is vortex on white 8!!!! She is double y 62!! I'll let u know what he looks like this year