Yes JS and JR work together. However you will find that the general consensus is to have JR to be roughly 80% of JS. This is the other way around by a long while too with pitiful JS and mediocre JR. While your assumption of 2 JR pops for every JS pop is roughly in line, his pitiful JS will take forever to get to a decent level. For examples sake, by the time that player reaches mediocre JS, his JR will be near prominent/prolific.
Will that sort of SG really be useful?? At the end of the day, JS is more important than JR. No point having range if you can't make the shot to begin with.