Clarification on using a reverse-proxy in front of OAM

Hi,

I'm re-doing a configuration and would like clarification on the best way to approach this. I have OAM 11.1.2.2 on http://oam.internal:14100. I want to front-end it with OHS 12.1.2 on https://oam.external:443 using OHS as a reverse proxy for OAM. The communication would be as follows:

  client ---(https://oam.external:443)---> OHS 12.1.2 ---(http://oam.internal:14100)---> OAM 11.1.2.2

I've tried the following a few scenarios with partial success so am reinstalling. The questions I have are:

Shoud this scenario require a WebGate to be installed on OHS 12.1.2 - I do have a WebGate configured for this?

Should the configuration look like this?: