Well, seems I am playing wrong game. After maxing terra master 8 finder you do not have any other finder to max(except those preamped like roctec cougr but they have low depth).
Also, what I am saying, there is no impact of finders on mining as there is impact of efficiency on weapon for hunting. Second point, since I am around lvl 80 on prospecting there is nothing above for me to use of finders or excavators like you have lvl 100 or lvl 120 weapoans, so skills are useless after e.g. lvl 60.
Anyhow, skills on mining (no mather is it prospecting,surveying, calypso ground assesment etc) should have more impact in my opinion.