I have been flying for many years and I have always owned at least one trainer. They are great for a confidence builder when you have been away for a while, great for after a winter with little or no flying to blow the cobwebs off, sometimes the need for a low stress day at the field and best of all to introduce someone to the hobby on a buddy box. In the mean time you get to learn how to fly and build experience. Don't just fly about without a purpose practice take offs and landings until you can do them perfectly even in adverse conditions. After that practice engine failures at different points in you flight from take offs and landing to altitude dead sticks. Of course any good trainer will allow you to do certain aerobatics. I have a couple of trainer that are well over 20 years old and still fly them off and on at least once a week. Mostly take them out now to introduce kids and adults to the hobby. My two favorites are the Telemaster 40 and an old old original Telemaster 66. The Telemaster 40 has flaps and this will help you get used to using flaps before you need them for your warbird.

You most likely will have to build these from kits so it will give you some experience in building from plans, shaping and forming some parts.

Pick a smaller warbird than the Ziroli something a little lighter and less expensive. I have flown Topflight kits before and they come in smaller and larger versions and use many different motors even convert easily to electric. Stuff like retracts and fiberglass parts are readily available.

Don't discount a warbird arf if all your looking for is to advance your skill set for operating a warbird. They may be a compromise as far as how close to scale they really are but they will give you the experience operating flaps and retracts. Every new operation you add to the flight makes your cockpit busier so having something that you don't have a ton of money or time invested to practice with will make your dream build that much better when it comes to your first flights.

Besides a project like you are contemplating will be an extended build so in the mean time you will be gaining experience and probably meet more than a few others who have already gained the knowledge you will be needing and with luck they most likely be willing to share with you.

Good luck.