how can you be absolutely sure of things?

The only thing you can chart is what YOU see. Did you see capillary refill happen? If you didn't you didn't, if you did you did. I'm not sure what 'adequate' would be. So on the strength issue, is there a measure you can use? equal bilaterally? Is the grasp strong (almost hurts your fingers?), or can you barely feel it? Adequate is hard to measure. Try to use words with value. Numbers. Scale. But it has to be what you see or think, and I'm thinking if you got this far you know what you see. Another person MAY say differently. That's their problem. Chart what you see and feel. Be specific. Cap refill in under 3 seconds? or Cap refill in > 5 seconds? 10? None? Write exactly what you see.

Oh, and there aren't a lot of absolutes. Even dead isn't necessarily absolute. So being absolutely sure isn't usual, or even necessary. You just do the very best you can. As accurately as you can. But don't worry about absolute. I'm not even absolutely sure I paid my heating bill. I'd have to look. wry grin. Life is lived on a gradient. More. Less. Sort of. Don't worry!

It's just your opinion on things. I mean, if my patient is a 6'4" 220lb male, I assume that when I ask him to squeeze my hand that he can make my hand hurt...and I want to see that grip strength....but of course if it's a 4'11" 100lb 92 y/o lady I would not expect her to do the same thing, but both may have "adequate" strength based on what I feel would be adequate for their age group.

As far as cap refill, 3 seconds or less is good. Below that is definitely slow. If you aren't getting color change when you press, you are either not pressing hard enough or you're looking at pallor (which is a bigger worry of it's own!).

But yes, it's just your opinion. Are those pupils sluggish, or brisk? Are they really equal? One might be 3.5mm the other might be 4...hard to measure that exactly. Just your judgement, really. A lot of times when something is out of place enough, you will just notice.