You'll be pushing the limits going from 74-91. The most anyone has ever pulled in to my knowledge is a 15 degree difference.
To set it up, aim at the middle bird (i.e. 79) and max out your signal on that. You skew the LNB in its holder, not the entire dish. Then add the lnb for 83 to the right and 74 to the left of the main LNB. It takes quite a bit of playing around with different distances and skew settings to get the offset birds.
79 and 91 have the most sports feeds, while 74 tends to be news feeds. I rarely scan 83.
To set it up, aim at the middle bird (i.e. 79) and max out your signal on that. You skew the LNB in its holder, not the entire dish. Then add the lnb for 83 to the right and 74 to the left of the main LNB. It takes quite a bit of playing around with different distances and skew settings to get the offset birds.
79 and 91 have the most sports feeds, while 74 tends to be news feeds. I rarely scan 83.