Yep. No harm in pre-filling. Only positives. This is the way.
I agree. Also, it's worth noting that Lakespeed Jr who made the video I linked to is a certified tribologist (oil expert) who
scientifically tested prefilling vs not prefilling.
However, the OP said his filter is oriented horizontal and therefore can't prefill it. That somewhat makes sense. If the filter is horizontal then it can't be prefilled as much, but it can be partially prefilled.
When I had a Jeep 4L with horizontal filter, my cousin used to prefill the center hole. Then let it sit on a counter for 5 min. It would soak up the oil into the filter's paper. Then he'd mount it and none spilled. It soaked up about ⅓ quart of oil. It was a large ⅔ quart filter. So it is was 50% prefilled with no spillage when he horizontally mounted it.
My Buick's filter mounts with hole facing upwards at 45° angle. So he is able to 75% prefill it with no spillage during mounting. 50% soaks in, then he adds another 25%, then mounts filter with no spilling.
As for the concern some people have that prefilling might introduce contaminents, here's my thoughts. New oil is clean and free of contaminents (as indicated by common sense and also Lakespeed tested this and proved it in his video).
Contamination could enter filter during mounting whether filter is prefilled or not. The only thing we can do about that is be careful when mounting.
The most likely source of new oil filter contamination is low quality filters often have a few manufacturing material debris inside the center big hole (oil exit area). Sometimes that happens with high quality filters too. For examples... A few small loose pieces of metal, filter material, or loose pieces of glue can be in the big hole (as was previously posted by other BITOG members in other threads).
I recently found and removed a small, loose piece of glue from my Oreilly Microgard Select filter's center large hole (oil exit area) before it was installed. If I hadn't removed it, it would have gone into engine. That's a premium filter made by Premium Guard. It's same as a Napa Gold filter.
It's a good idea to always look inside filter center big hole (oil exit hole) to see if there are loose pieces of anything that can be removed before installing filter. That applies whether you prefill or not.