take it from me 1 on 1 for forwards makes things harder for you to compete on court especially when your trainees are shaped like PG or SG rather than SF or bigger. You might be fine in your league, but for me it made a real difference. You also get to train 2 positions when you do this so its always handy to have some other guys in your team who can benefit from this aside frm your top 3 trainees.
I'd be tempted to increase his IS once (to mop up any partial level he has right now) but each extra IS pop would take about 8 weeks doing 1on1 for forwards at his age. and in this time his JS wont be going up as fast as if you trained 1on1 for guards.
if you have aspirations for u21 (or just having an awesome player) he'll certainly need more OD whatever the rest of his skillset is so you should plan ahead for this.
at 7 / 7 for JS and JR, if you want him to be a real SG by the time you finish training him you will probably need to train some JR at some point as well as a mega lot of JS. I would only train JR if you see the JS/JR growing too wide for comfort. If you train JS specifically, JR is trained as a secondary skill.
The level of JS/JR is down to preference and managers will differ on their opinions but mine would be for a JR that finishes around 12 and a JS at whatever you like and can afford. JR at 13+ starts gettng increasingly expensive and i doubt its value for money compared to other skill pops you might want to see on him.
Overall i would try to balance his development in his guard skills leading with his OD and then JS. 1 position passing is nice too up to your goal for him then you can see his handling and driving improve as secondaries too.