The answer to this is probably going to depend on the individual. I'm inclined to say it shouldn't be a problem except that you say it will be your main practice guitar.
I'm not sure what other guitars you'll be playing and for what purpose, but in my experience, it's best to practice on the guitar you will be playing in other (non-practice) situations. So if you're going to get together with your friends and play or perform, use the same guitar for both, or at least a guitar with similar geometry.
On the other hand, it generally shouldn't be a huge problem. Your fingers are used to dealing with variations in the spacing between frets. Think about what a longer scale guitar is like if you stick a capo on the third or fifth fret. There could be issues with string tension, however, unless you accommodate by putting lighter gauge strings on the full size guitar.
I think you'll get better results sticking with one particular guitar or scale length and reserving something like the Parlour guitar for travel or other situations where its smaller size is an additional advantage over a full-size guitar - unless you plan to use the parlour guitar for everything and treat full-sized guitars as novelties.
FWIW, I believe the two most common scale lengths are 24 3/4" and 25 1/2". So a "full-size" guitar you go to grab might have either of those scale lengths, although I believe 25 1/2 is more common.