While I've tried using an RB67, I found the ground glass and heavy size to be very cumbersome... and I found out all too quickly that my brain doesn't work really well with my type of work (quick reaction) with flipped orientation. Also, much prefer the "wide" aspect ratio of 4x6 (in comparison to 6x6 square or even 6x7 semi-square) so am curious about the Texas Leica!