First of all, HP and OD are way too high. At least for a map with 3.79 SR. I was even dying during the play tests xD
It only just got out of range for hard and it's already at both 8 HP and 8 OD...
Also AR 9 isn't really necessary imo.
It almost feels as if you're trying to push it to become a harder difficulty than it should be.
The settings should only be a supporting role imo, to get the difficulty correctly balanced, not to make it harder than what it essentially is.
Here's what I recommend (keeps in line with previous difficulties as well) (also tested it, works fine):
HP 7
OD 7
AR 8.5
00:23:390 - Ouch this slider velocity is sudden. Try slowing it down or simply making it a circle instead.
Unless you know that it'll be there, it's really hard to tell that it'd increase to 2.25 times the previous SV.
00:33:576 (7) - Circle is hard to see in this skin, I'd have placed it on 00:33:688 (1) - , since the two sounds are quite similar.
00:58:987 (6,7,1,2,3,4) - 00:59:658 (1,2,3,4,5) - Square streams like this is hard to follow accurately, I'd try curving it instead.
Something like this, for example. Will likely flow better as well, depending on how you'd position 01:00:106 (2,3,4,5) - .
01:03:688 (7,8,1) - I'm quite sure spacing like this with 1/2 is going to get confusing right after the same spacing with 01:03:241 (4,5,6) - which is 1/4.
I'm sure just stacking one of them will work better, as there will be a difference between the two in spacing.
For this case I recommend stacking 01:03:688 (7,8,1) - , since most 1/4 streams aren't stacks.
This way it'll be more readable, otherwise you'd probably have to NC them, which wouldn't be preferable due to the combo health boost.
^ 01:09:061 (5,6,1) -
^ 01:16:226 (8,9,1) -
01:19:584 - A bit of overlapping here
could rotate 01:19:360 (1) - like this:
Other than some difficulty settings, patterns and spacing, this difficulty should probably be fine.