How much does a PRS McCarty 594 weigh?

PRS McCarty guitars typically weigh in the region of 7.5lbs to 8lbs.

How does the altered scale length of the McCarty 594 affect the feel of the guitar?

PRS normally use a scale length of 25"" which is already sitting somewhere between the two traditional values of 24.75" and 25.5". Some of their models like the Santana guitars use a smaller `scale length again with 24.5". This is almost 'short scale' and the benefit for the player is a much easier, less tight feel on the strings as the tension is less great. You can bend notes easier, perform vibrato with less effort and generally feel more confident and comfortable on the fretboard. The McCarty 594 is a little longer in scale than the Santana and still a little shorter than the traditional 24.75. This, according to Paul Reed Smith, is a real sweet spot in terms of getting the best feel and tone from the shorter scale guitars. Intonation is reportedly much more precise too and is in fact the main motivating reason for making these minute differences in measurement across the fingerboard.