t-amp connecting two sets of wire from terminals?

Another audio guy said yes but I want a confirmation...however I did already do it want to make sure it's safe in the long term.

On my computer I just got a new Topping TP30 T-amp and a set of Micca MB42 bookshelfs...awesome clarity and definition with these by the way... excellent.

I have a paradigm powered sub that only has inputs, I simply ran an extra set of wires from the topping binding posts to the high level terminals of the sub, since it is only taking the signal will this cut my impedance? The micas say 4-8 Ohms, I believe the amp may be the same.

Any input here?
Also a newbie question but is there a cleaner way to attach two sets of 14 gauge wire to one terminal? will two banana plugs fit in a binding post hole?

thanks for any help guys.