Mendocino - Help!!!

I'm working on the Mendocino cardigan (Pacific Coast Highway) and I'm confused by the directions. The gauge calls for 19sts and 24 rows over 10cm using 5mm needles; mine is 19.5 sts an 29 rows using 4mm needles. Right now I have 26.5cm in length with 85 stitches on the needles. Here's where it gets confusing - she has you increasing until sleeve measures 34 cm, then starting the chart pattern over the center 27 stitches (notice that she does not say how many stitches you should have on the needle at that point). And then continue to increase until there are 99 stitches, and continue without further shaping until sleeve measures 44cm. What I'm confused is how long the sleeve is when you have 99 stitches. The diagram shows a diagonal edge to the sleeve, then bindoff straight across to create the saddle.

Now, obviously, my row gauge is seriously off the mark. It's not so bad for the front and back since the only shaping is created by the cable ribbing which pulls in the pieces. I've already got the front pieces done and will start on the back after the sleeves are done. My desired measure from shoulder to wrist is 47cm (18 1/2 inches); I know the sleeve will be somewhat shorter than that due to the saddle shoulder and the fact that the edge of the sleeve will be hanging a bit off my shoulder.

So, how should I adjust the sleeve directions to take into account of my off-kilter row gauge?