You'll likely get good $$ from REA. They get good prices and wouldn't accept anything unless it was quality. They're picky.
Sounds as if you have some nice stuff-- which is of course good for your situation whichever way you sell. If you had a busload of 1988 Donruss, I'd say 'Uh oh.'
In general, I'd see what major auction houses are willing to take as a start.
Starting an eBay store rght now and putting some thing up sounds like something you can do in addition. It costs nothing to start a store so there's no $$ invested. You can start with ten items and see how it goes. You can consign and put things on eBay simultaneously-- not the same items, of course
As noted, you can list items on the B/S/T.
Major dealers don't sell just one way-- they go through different avenues just as you can do. Even major auction houses sometimes have an eBay account to sell their extras. So selling some this way and some that way, some now and some then, isn't abnormal.
But for someone who hasn't sold before, getting stuff (if not all or even the majority of stuff) into a major auction house is a good deal.