I have an A-27 that I also got recently from a thrift shop. It’s green. It came with no case or mouthpiece and has a significant crack across the mouthpiece end. It leaks a bit but plays well. I haven’t taken it apart yet, but there’s no choking. The reeds on these models are different. They are hard to gap. I have one reed on a Study-25 (same vintage, roughly) that was pressed below the reed plate. I had to partially remove the read plate to get under it and push the read out to where I could get something under it, and I’ve been working for several days to open up the gap, but the reed is much more resistant to having its gap changed, and the note is still not playing correctly. I have made some progress by applying heat (with a hair dryer), having been advised that heat would temporarily change the properties of the bronze. The Study-25 (A-25 really) reed plate and reeds were discolored, and one of the screw heads was rusted. But otherwise they seem to be in good shape. No clogging issues with either one, though I’m not sure exactly what you mean by that. “Clog” makes it sound like a moisture issue and makes me wonder if yours is venting properly.