Toba: I used your tactics, then mine>> Below
Bring shock traps and the things to make 2 more.
Sonics, flash, bomb making thingys lol..
DO aviod hitting the horns (If you want the monster to go fastest, Combine toba, and I's way of doing it TOGETHER!)
Have a strong Great Sword, like Darkness Darkblade, Ukanlos Destructor (Not yet unlocked for Tigrex
) Gaoren Cleaver is the best weapon against the Black Blos..
Scince the Blos constantly run, use the gs to have a large damage dealt in a short period of time.. (Before i had any of those weapons I used Crystalyzed Tuna, It took me about 45 mins for both..)
In the begining of the fight use up ALL materials for bombs and traps, then attack only when the time is right.. If your a good hunter you will know when that is.. Being as your HR 9, you should be really good.. ALSO Sometimes i go after High rank Black blos a few times to get used to the attack patterns, scince High rank and G rank diablos have the same patterns.. G is just faster.
If the Blos gets stuck in a wall heres what ya do: Run to its tail (with sword AWAY!!) and press Triangle, O, O and triangle, O, O and triangle, untill hes out of the wall..
Using this tactic mixed with thngs from Tobakado's tactics, I killed both of them with C.Blango Destructor in I think 20-30 mins.. SOLO!! Fastest Solo G Dual Diablos fight for me ever!
Happy Hunting!!