Oky, let’s try to understand each other 
- For “Horizontal scanlines” do you mean: “===” or “|||||” ?
- 1024x768 is indeed quite difficult to manage for “==” scanlines, even more if you plan to put curvature into the equation, because of weird articacts that may arise, like weavy patterns without curvature or moire for curved screens.
- What’s the real monitor? I’ll assume a 4:3 1024x768 LCD.
- What size (inches or cm)?
I’ll try to craft a preset starting from the same base preset you were trying to tweak.
For such low resolutions (assuming low dot pitch here), trying to emulate phosphors triad can be challenging, and indeed it leads to too wide patterns (I think this is the issue with the “dots” too far apart you mentioned).
You can mitigate that by using a 2 sized mask => mask type preset set to 1:
Which will give you this:

- Slotmask/Curvature:
Unfortunately low vertical resolution is not enough to emulate real slotmask with accuracy; But there are some workarounds you can use.
First is to disable real slotmask emulation:
…next is to enable fake slotmask emulation which, instead of drawing staggered tiny gaps vertically between phosphors, staggers the scanline itself; the value 0.18 is important, read on.
this will give you something like that:

On such low resolution, koko-aio automatically switches to “fake integer scanlines”, which is a rude way to draw straight lines which align to the real screen lines, but are not curved and won’t follow the content you are emulating (to make it easy, instead of drawing a line for each core line, it will draw a straight line every 2 screen lines).
That way the weird weavy or moire patterns mentioned earlier are “bypassed”
However the fake slotmask emulation we just enabled in the previous step has the ability to trick the brain, somehow hiding those patterns to the eye, so we are going to tell the shader to draw proper scanlines.
(The “0.18” earlier set for fake slotmask parameter is the one that is able to hide moire on 768p)
Next tweak is about the scanline gaps; I think your Hantares has well defined gaps, so I’d lower the min/max scanline height to 30…50 range (do not set minimum to less than 25 or moire will be visible, you can still lower the max from 50 to 30 for steeper/darker/better defined scanlines) and contextually I’d disable Haloing and any vertical deconvergence to leave those black gaps, black.
Your hantarex:

Parameters:
However haloing helps in retaining brightness, so I’m going to trade mask definition for a brighter image by highering the maximum
phosphor width:
Next step is to push some more bloom to gain even more brightness; white blooming has the ability to give you more lumninance while keeping good mask definition.
With some other smaller final tweaks to the output gamma and color corections you can see in the attached preset, we have the following:
Put the following preset in the same folder as to koko-aio-ng.slangp (or change the #reference line)
1024z768_v3
#reference "koko-aio-ng-slangp"
GAMMA_OUT = "0.380000"
DO_CCORRECTION = "1.000000"
IN_GLOW_POWER = "2.000000"
LUMINANCE = "0.100000"
TEMPERATURE = "7300.000000"
VIBRANCE = "0.000000"
DO_SHIFT_RGB = "1.000000"
OFFSET_STRENGTH = "0.250000"
DO_IN_GLOW = "1.000000"
IN_GLOW_BIAS = "0.000000"
IN_GLOW_SPREAD = "1.700000"
IN_GLOW_W = "7.000000"
IN_GLOW_H = "7.000000"
DO_PIXELGRID = "1.000000"
PIXELGRID_COREY_FAKE_SCAN = "0.000000"
PIXELGRID_MIN_H = "0.300000"
PIXELGRID_MAX_H = "0.500000"
PIXELGRID_GAMMA_H = "3.000000"
PIXELGRID_OFFSET_CORE = "0.180000"
PIXELGRID_H_DEDOT = "0.700000"
PIXELGRID_H_PRST = "1.000000"
PIXELGRID_MIN_W = "0.050000"
PIXELGRID_MAX_W = "1.000000"
PIXELGRID_BASAL_GRID = "0.020000"
PIXELGRID_Y_MASK = "0.000000"
PIXELGRID_Y_MASK_HEIGHT = "-2.000000"
PIXELGRID_Y_MASK_OFFSET_DEHIVE = "0.700000"
PIXELGRID_Y_MASK_ON_WHITE = "0.000000"
HALO_NO_PREGAIN = "1.000000"
HALO_POWER = "1.000000"
HALO_SHARPNESS = "7.000000"
HALO_GAMMA = "1.000000"
HALO_GAMMA_OUT = "2.350000"
HALO_VS_SCAN = "0.260000"
DO_BLOOM = "1.000000"
BLOOM_MIX = "0.400000"
BLOOM_SIZE = "1.000000"
BLOOM_GAMMA = "4.000000"
BLOOM_GAMMA_OUT = "1.600000"
BLOOM_POWER = "3.500000"
BLOOM_EYE_ADPT_SRT = "0.600000"
DO_CURVATURE = "1.000000"
DO_BEZEL = "1.000000"
BEZEL_REFL_STRENGTH = "0.370000"
BEZEL_DIFFUSION_STR = "0.150000"
DO_GLOBAL_SHZO = "1.000000"
GLOBAL_ZOOM = "0.991500"
DO_VIGNETTE = "1.000000"
V_SIZE = "1.200000"
V_SHAPE = "0.800000"
DO_SPOT = "1.000000"
S_POWER = "0.067000"
ADPT_STROBE_STR = "0.000000"
I think this could be a good starting point for you to further tweak as per your likings, If you haven’t already, please take a look to the docs-ng.md file, which documents all of the parameters.