loyalty on gc on a single cluster or planet doesn`t effect the dig, by this i mean a 5,000 loaylaty on a u spaz doesn`t get you anymore orbs etc than a 50 loyalty one.
But
rewarding the act of rewarding raises your luck on gc which in turn raises what you`ll get on a dig, more luck = better items or more items, hence why certain dig times work best because luck is raised in those periods, and why regalos work best at those times.