Truck wouldn't start on Friday, rapid clicking, after a lot of effort I got it jumped, ran fine home (but voltage dips when engine RPMs would drop... so alternator power really), when I got it home, wouldn't start again... so obviously an electrical issue.

So upon inspection of my negative battery cable and it's ground, both were heavily corroded (multiple cuts to both cables to too-short lengths revealed corrosion), replaced ground, replaced the negative cable, in my haste I didn't take note that I need a "Y" cable to tap into both the engine block and the negative on the fuse box (in which case.... why do they sell direct cables?! Ugh!), so I tapped it to the fuse box...

Now, with the old wire still tapped, I can get the truck started (being as it provides negative to the block via my new wire). My question is whether or not this is something I should immediately undo and redo (as in don't drive the truck at all, go buy another set of cables, etc. etc.), or if this is just messy practice and a mechanic will look at me sideways when he sees this.

1999 Ford Ranger, 6cyl if it makes any difference.