Yes, as an 18 mm shot, that is excellent. A higher angle might have helped the distortion problem but in a Catholic church, that is hard to do, in a manner that is not inappropriate.
Plug-ins such as Dx0 Optics Pro would be ideal but they do not I think have much in the way of Minolta related software.

I have never used the converters, so I really can't talk about them.

Ronnoco