All my opinions and probably what I would do:
The oil tube, unless it was blocked, was probably not the real problem unless they're all bad. It was still bad manufacturing. I would just put fresh oil in it. The C-10 has a wet clutch so anything you add will ruin the disks. If you are that concerned you could remove a few of the supply lines and flush them out, but probably a waste of time. I would just consider a little more frequent oil changes with a fresh filter each time for now. If it was me (IMHO) I would use synthetic (and I do, Rotella-T6). You can pick up the Walmart house brand or the better Rotella-T6 for a good price, especially since you might be changing it more frequently now (for a while). Also, just a reminder, the C-10 has TWO drain plugs - not including the filter itself.
Since you are in there already, you may want to consider changing the thermo to make sure it is keeping the engine as hot as possible. You can actually use one from a car. Tell them you want one from a 1983 Honda Accord. The model doesn't matter. Get the 192 degree I think it is. Order the O-rings from the local dealer or online (2 if I remember, a big one and a smaller one) for the housing before you start though as they usually dissolve into black bubble gum over time and you won't be able to seal it back once opened.