Correct HV_CAP thickness and allow STD_DEVIATION to be handeled as an array

Taking care of the unproblematic part of the fixes discussed in !196 (closed), !247 (merged) and #156.

This new MR doesn't completely replace draft/MR !247 (merged) as that contains another fix, that is yet still to be discussed (see !196 (closed)). However the final decision about this will still need some time and the other fixes are blocked by this otherwise.