You have probably already brewed. I think you can cram your recipe into that small mashtun and if you fly sparge and stir it while sparging you can probably make it work albeit somewhat inefficiently. I went to a 15.5 gal keggle for my mashtun and never looked back. It works great for all sorts of batch sizes. I can even do close to a 15 gal batch, fly sparging and babysitting the boil that is close to the top of the keggle boil kettle.