The spring looks right to me. I'd put the slide lock pin in without the slide and insert an empty mag and see how the follower hits the slide lock lever. It may be that spring has to be turned down just a bit more.
In Memory of Paul "Dietrich" Stines.
Dad: Say something nice to your cousin Shirley
Dietrich: For a fat girl you sure don't sweat much.
Cue sound of Head slap.
RIP Muggsy & TMan
"If you are a warrior legally authorized to carry a weapon and you step outside without that weapon, then you become a sheep, pretending that JOCKO will not come today."