I checked you numbers and they look correct.
Here are some suggestions:
1. Use a systematic approach - - - by that I mean set the skew and forget about it. Start a bit high on the elevation and work the azumuth back and forth in very small increments. Then lower the angle one degree and try again.
2. One time my 9 year old helped me by using a Walkie - Talkie (I was on the roof and he was in the house watching the signal from the receiver)
It can be very frustrating when you cannot find the satellite but I have found the systematic approach to be much better than a random method.
Lastly, since DirecTV has signals at 101W and 93W if you have an old LNB from DirecTV you could find those two and then go half way in between. This sometimes helps since DISH and DirecTV put out so much greater signal than Ku band.