You say you want to build you second plane. Good on you!!!

Do you mean scratch build from plans, or build from a kit?

If you build from a kit, the designer of the kit will have thought about engine access for you( if the model has a cowl, that is), by making the cowl removeable, or allowing enough clearance to remove/fit your engine with the cowl in place.

If you scratch build, the world is your slimy bivalve.

Most designs featuring cowled engines allow for access as well, although some are better than others. In the end, it's up to you. Plus, models can be cowled simply with balsa, and do not necessarily require skills with using fibreglass or other exotic(?) materials.

Good luck with your project,

Chunkylad