Hey David. Youll not get more than around 80% for strength or quality, unless you have a 100 foot dish. 80% for both will produce a full picture.
Offset dishes dont point in the direction the dish seems to face, the sweet spot is low on the dish face generally where the mount bracket bolts are, and the dish point angle is much higher than both the dish face and LNB position would appear to suggest. Having a completely tree, building and obstruction clear view of the sky from almost ground 90deg up, and 180 deg from directly in front will at least eliminate signal blocking. Leaves might as well be brick walls. If you have Wikicamps use that to get a rough indication of where the Sat is positioned in the sky. The phone App finders and phone App compasses are great initial indicators, but are certainly nowhere near 100% accurate. On a phone App Sat finder the Sat will be located off to the side of where the App says it is (as hard as a try I can never commit to memory which side that is). Then use your signal strength meter to manually tune it in. Skew is important but a little forgiving at the same time. The notches on a Strong brand LNB indicate 5deg increments, I can only presume other brands use the same scale. Your pointing can be spot on, but skew way out will not produce a picture. For reference, LNB skew at due north is around 35deg from centre, 6 notches on the LNB but at 4 nothces youll still likely get a picture. Once your up and running its a good idea to adjust the LNB in both direction to get a feel for its tolerance for you own knowledge.
Your signal strength meter is powered by the Sat box, and will make noises and light up even when the connecting lead from it to the LNB is disconnected or more importantly faulty. If that's the case the signal meter will look like its working, but could be getting no signal from the LNB. As unlikely that may intially seem, Ive experienced that exact issue many many times over the years. Experience tells me a difficult tune is likely to be the connecting lead or connections on that lead between the signal meter to the LNB.
The Intelsat 8 Sat is very close to the Optus C1 Sat, and although its a lessor signal strength if your using a phone App you may be pinging off the Intelsat 8. The Optus C1 will squeal louder than the Intelsat 8. @Drovers Satking map link is actually the USA based
www.dishpointer.com/, where you select your Sat and location and it produces the specs for dish setup. The line it produces on the map will give you a local landmark, such as a neighbours house roof or distant tree to point the dish without relying on a compass or phone App to get you starting point. Use the skew on
@Bellbirdweb's linked PDF, the skews on
http://www.dishpointer.com are not accurate for our hemisphere.
As mentioned by
@Drover, keep the dish wingnuts loose'ish and move the dish up and down, and side to side in small increments until you get the loudest indication; the final tuning steps will be very slight nudges and almost down to dish flexes.
Emerald elevation is 64deg, so quiet steep. Mounting brackets have a series of holes that allow the dish to be moved on the mount to allow higher ponting. Ensure you have the dish mounted through the bracket holes that allow the dish to point at 64deg angle.
I use the cheapest $5 signal meter, which I had for 10years (simpler looking version of yours) and it never lets me down. once you get the "knack", it will all fall into place