With a typical LNBF, I could get six-degree spacing on my 90cm dish. 103W center, 97W, 91W all came in well
For four-degree spacing, I switched to skinny LNBFs. 103W, 99W, 95W, 91W all come in fine, but it might be tough on a smaller dish.
I figured I'd include the pics so you could see...