Currently here's what I think will happen:
1% chance of a Cruz 20+ point win
2% chance of a Cruz 15-19 point win
15% chance of a Cruz 10-14 point win
55% chance of a Cruz 5-9 point win
26% chance of a Cruz 0-4 point win
0.7% chance of a Beto 0-4 point win
0.2% chance of a Beto 5-9 point win
<0.1% chance of a Beto 10-14 point win
<0.1% chance of a Beto 15+ point win
FTFY
You do realize Cruz is only leading by 6, whereas Sherrod Brown, who you think is very vulnerable, is leading by 18?
'very vulnerable' is an exaggeration. I have Sherrod favored to win. Furthermore, I simply don't believe there are enough votes to elect a Democrat in Texas regardless of the environment.
If Alabama can send a Democrat to the Senate, then so can Texas. Don't be dense.