Welcome to CFC, celicagrl00. Regarding Resource Seeds numbers, they repeat every 64, so #65 is the same as #1. I've seen some numbers in the tens of thousands that I think are set by the map randomizer, but if you do a modulo 64 you will see that it is the same pattern.
There are four basic arrangements of the two different specials (Whale-type and Fish-type) is groups of eight on a diagonal, running in horizontal bands 16 tiles apart. Changing the Seed number within one pattern (like shifting #1 to #2 or #3) moves the horizontal bands vertically a set number of tiles (10?). Adding 16 to a Seed keeps the specials in the same place but changes their type (and moves the Huts around - their pattern depends on the Seed as well).
It's hard to answer the question "Is one better than another?" - that depends on how you define "better". What are you looking for? The answer is different for Food, Trade and Shields. A lot of players seek a site for their SSC that has 4 high-Trade specials as well as lots of grass and rivers. Gold is the best for Trade, but among the worst for Food. The one number you do NOT want to use when designing the "perfect map" is #1: when you load the map to play it acts as a randomizer and your alignment of specials with terrain will change. Use #65 if you want the same alignment as #1.
No, you're not the only one to notice the shielded grass pattern: it's hard to miss if you draw all grass in Map Editor. Early on people thought only non-shield grass had hidden specials under it, but study of the special patterns debunked that myth.
