Don't add a jib.

First, it will compromise your upwind performance, as jibs are useful really only for reaching. A jib, upwind, creates more drag than lift and you can't point as high. The sail area isn't enough to be really useful sailing deep downwind. That's why all these people add chutes.

If you note, a lot of the 'hot' new designs are going with the unirig configuration with a chute. Best of both worlds. Reference Marstrom 20, I-17, Javelin, etc.

As for your under-trampoline pole, that's a 'righting pole' and you stow it by drawing the pole up under the tramp and bungee-ing the pole somewhere on the aft crossbar.