2x 4s to 8s balance connector

Ok so i am ordering a power supply for my 8s charger and i was wondering how i could connect them together with out much soldering also what would i charge it at it would be two 4s 5000mah batteries 30c.

personally I would buy one of these leads and then cut the connector in half(ish) (5 one half and 4 the other)

like I do in this video

(only i did a 6S so I only have 4 and 3 pins) same principal.

Thanks for the advice