I'm thinking of buying in to the Godox system and starting with a couple of AD200's. I know that they will fit in a "bowens" mount. But I am having trouble identifying a good selection of modifiers that I will have available. I can probably adapt them to about any umbrella system, but I'm not so sure about softboxes. I want to pair them to a nice big softbox. I only see one Westcott product that uses the bowen's mount and that is the Apollo ORB. It is pricey. I realize that Godox has their own selection of modifiers but they are all fairly small. How can I determine what modifiers I will be able to use easily with the Godox light system?
On their own AD200s do not use Bowens mount modifiers. The bare bulb head of the AD200 uses the mount of the old (now nearly defunct) Quantum Q flash system.
If you want to use a Bowens mount modifier you need to use a Godox S-type Speedlight bracket or a Godox AD-B2 bracket. The first one is very inexpensive and holds a single AD200 the second is slightly more expensive but will allow you to use one or two AD200s to give you up to 400Ws of power plus a modelling light. The Bowens mount is the most common mount supported by third party light modifier vendors. Just google Bowens mont modifier and see. The Westcott Apollo ORB is NOT Bowens mount softbox.
You would probably find this overview of the Godox lightning system helpful before in deciding what you need to start out withhttp://flashhavoc.com/godox-flash-system-overview.
If you do go with the AD200 (which is an excellent light) you will need the appropriate radio trigger top go with it. I'd recommend the Xpro.