Export vector made wit custom intentsity brush without get rasterised?

[Johnny Chin]

Hey guys, I have an 8 x 10 inches file and I want to create custom vector arrow that Affinity default shape doesn't provide. I did it by using "New Textured Intensity Brush" and used a B&W image(black background and white arrow shape), the image size is 2048 px^2, I adjust the setting so the brush will always has the arrow head in front and nothing behind, but I have to set the brush width to a lot bigger to get a usable size. For example, in the brush width i set to 85.5px, but in the stoke width setting I have to set to 20.5 pt and then everything looks perfect, but when I export, they all get rasterised, I guess they fall into the "unsupported properties" category, so I change to rasterise nothing in the export but then they become so big in the exported file, what should I do?

I hope to keep them as vector in their intended size so that I can overprint them on top of image and keep them as high quality as possible, I afraid if I rasterise them, the pixelated edge will make the printing has issue since they are so thin and might cause color shift, or they won't be printed because these pixelated edge are just few pixels size? 

[v_kyr]

See the available line style start/end arrows ...