I just started reading this board and find it very interesting.
To add a few additional comments:
this question has been discussed on several other boards - an argument that arose at one time regarding whether the practise of prefilling was recommended or not, prompted me to reread a number of repair manuals I'd been using - many of them actually did recommend prefilling. I had always done it anyway, and even on engines that had horizontally mounted filters.
The next time you remove a used filter, turn it on its side and see how much, if any oil actually spills out - then cut the casing, or punch a hole in it. You may be surprised to see the amount of retained oil.
It is surprising how much oil will be trapped in the media and in the outer area of the casing. The oil in the center tube is a minor portion of the oil contained, and it's only some of that that that will spill out when the filter is turned horizontally.
BTW, it takes a few minutes of repeatedly filling the center tube before enough oil is absorbed through the media to fill the entire casing. The time taken is not critical, I presume, since you're only working for yourself here.
The fact that fast lube places don't prefill is no justification to not do it. As already mentioned the attitude should be that there is no reason to not do it, and there is a reason to do it - hydrodynamic lubrication is always better than no hydrodynamic lubrication, even for a few seconds.