I am not quite sure on what exactly you want to know but here is a bit of information for you.
On my 2017 Spartan I have a 1.5 degree works headset installed that drops the stock headangle of 65.8 in the low setting or 66.4 in the hi to the obvious 1.5 degrees less for each. But that is not all, it also changes other this slightly as it lowers the front end. So the bottom bracket will sit slightly lower, the seat tube will also be slightly steeper (better for climbing) and the reach was also ever so slightly decreased.
So for how it handles in my opinion is better as I regularly do a large climb for the longest steepest decent.
I can add some of my experience, I did the same - bought -1,5 angleset from Works for my 2016 spartan (Im running 160mm pike). Reason was that right from start I felt that even in low settings HA is just too steep for my agressive/downhill focused riding style. I cant praise more ... for ascending it transformed bike only in the good way, more confidence on steeps and fast lines and I havent noticed any downsides in handling, BB has still enough clearance even with 175 cranks and STA I dont feel any difference honestly. Uphill I think change is almost unnoticable.. all fine.
What I would like to highlight is that originally I wasnt sure if 1,5° wouldnt be too much (was considering 1,0°), but now Im glad I went for 1,5.