Thanks for taking the time to give me all that information! I had thought Hohner was making a Corona with LMM but couldn't find any information. I know the quality of both Guerrini and Dino Baffeti because I owned piano accordions from both manufacturers.
There is a Dino Baffeti dealer about two hours from me but for my first triple row I want to buy used.
I like your advice about the Roland. I haven't seen one for sale in a long while but I suppose if I search more seriously I could find one.
I would prefer a LMMM which is the setup of the pa Guerrini I owned. But ai am trying to get away from the weight of accordions with four sets of reeds except, of course, for the single rows I own.
Thanks again. I'll keep looking, be patient, and wait for something to show up. I no longer play in a zydeco band, wher I was playing piano accordion, so I am not in a rush. A three-row initially will be to satisfy my musical curiosity and give me another accordion-playing challenge.