Maybe this seems like a Noob question,
but as long as I can remember, all my guitars
have the "arrow" configuration for the tremolo springs
I'm trying now a guitar that has same string gauge,
same tuning, same scale, same everything, except the spring configuration,
and I feel like the string tension is way heavier
and I feel playing is a little harder.
I know that the spring configuration affects of course the
feeling of the tremolo, but is that affecting also the
way the strings feel under my fingers?
If you're using the same string gages in the same tuning, then the string tension is no different from before. Tension is directly related to string gage and pitch. Well, the other way around, anyways
What you might be experiencing is a slightly different spring constant. All springs have a force constant, k. You may remember Hooke's Law from high school Physics. It's the same thing. Only, springs aren't always as uniform in real life versus in theory, so there's probably a k gradient as you stretch the springs. Changing the length-stretch-at-rest of the springs in the back could be changing k on them, thus changing how you might perceive the tension on the strings when you do a bend, vibrato, etc.