I installed a Craven Speed phone mount with the new extra large scissor mount and the 5" arm. I found that the 3" arm that is standard was too short and the phone ends being partly blocked by the steering wheel.

 

Question, does the scissor mount hold the phone really secure? I opted for the magnet mount cause i was worried the scissor mount wouldn't hold my plus sized phone.

 

It depends. The scissor mount holds my Galaxy S8 just fine. On the other hand, my iPhone 7 with the Apple smart battery pack will slip off after driving through some rough roads. I can't use the magnet mount because it would interfere with the wireless charging. I originally had the big clamp they offered but the phones would slide down slowly.
I do have an alternate solution. I used the ball mount that Craven Speed offers and mounted the iOttie Easy one touch 4 mount on it.