Welcome, I started out by buying an entry level watch from Jackson and modding it. I used the DIY section and the disassembled the watch. This allowed me to measure the dial and order a new one in the proper size. Eventually I got into aging dials, hands, cases, painting, luming etc. However, I was pretty happy with a simple dial swap and some aging to start.
I would highly recommend getting one for under $100 and practicing by taking it apart and putting back together.
Don't forget to ask lots of questions along the way, we're all happy to help.
Here's a link to Jackson's stuff. You can click the drop down arrow beside Marina Militare and filter by size.
http://www.militarytimewatch.com/new/pr ... atlv1_id=7
