Cat5e cables have 4 twisted pairs, eight cables in total. If I only needed 4 cables (2 for video & 2 for power) would it be better to use two cables instead of one to double the amount of wire being used? If it is better to use two cables for each connection then does it matter which pair of cables I use e.g.

. video use blue/white for positive and brown/white for negative

OR

. video use blue/brown for positive and white/white for negative

I presume these cables are twisted for a purpose but does it make any difference in this scenario?

BTW - cable length is around 35m.

Video should really be on the same twisted pair, as the twists cancel out electrical interference.

You can use extra pairs to carry power, so you get less resistance, meaning less voltage drop.

and some more advice about cat5 cable on cctv use active or passive baluns on both ends as without them you may find there will be interference. active (that dont need power) would be fine for that type of run

hope this helps.