Here sight represents evaluation and judgement. Alternate translation: "In our own opinion ... in their opinion" or "In our own judgement ... in their judgement" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The men speak of grasshoppers to show how very small they thought themselves to be compared to the people of the land. Alternate translation: "we are as small as grasshoppers in comparison with them" (See: [[rc://en/ta/man/translate/figs-simile]])