High Test appears to have an interaction with at least some of the different lures.
- Extreme Sinking Lure: High Test encounters occurred more often. (of the 100 fishing trips while paired 85 resulted in high test.)
- Extreme Fishing Hook: Gave objects priority over combat. No fights occurred while the pair was active. Of note it replaced the Shoreline terrible serpent result with the lakebottom result even while etheric.
- Extreme Floating Lure: Prevents high test fishing from occurring. Could actually prove useful for maximizing the +modifier if you do not want high test results. Once we know what it does and if it in turn needs maximizing that is.
The current question is if the impact is unique to the Extreme lures or the various modifiers they give. Which in the case of +deep and +surface on lures is unique to the tackle box. Using a lost hook with high test on the Shoreline while etheric and seeing if rocks come up instead on terrible serpents will go a long way in helping narrow things down.
I have yet to identify what if anything +actual fish brings to the mix. Both fight and object results happened on the Oil Slick so it doesn't do the reverse of +objects. It could have no interaction or something small/subtle like better odds of fresh mollusks when applicable.
Long story short: Work in progress.
Gone fishin', be back at dark-thirty!