On 103W Ku, 12080 H 29970 is the toughest to receive reliably. 12145 V 20000 is stronger and easier to lock. Right now, 12080 H 29970 is 10.1 dB and I'm viewing it fine. 12145 V 20000 is 4.7 dB stronger at 14.8 dB.
Your LNB is fine. I wouldn't bother changing it. You should be able to receive...