Will it increase his salary more then Inside shot - (reb and inside shot are both "big guys" abilits )
Only BBs know that... I think Rebounding and Inside Shot are both secondary skills for an SG, so the increase in salary would be approximately the same...
From my experience as an regular BB user and as an NT-Coach, the most important skill for SG is Jump Range... That adds the most to an SG salary... For PG, that's Passing... I don't know for sure what is the most important for other positions, but for centers it may be that all of the 4 main skills will increase the salary by same rate... For PF it's those 4 + Jump Shot, I think... And for SF, every skill is important and it's really hard to tell the difference... There aren't many SF-trainers...
For SGs, I know because i had this player with sensational Jump Shot, and only respectable Jump Range and he had ~10k salary... In NT I had similar player with prominent Jump Range and he had ~20k salary...
For PGs I know for sure, cause one NT PG had 17k salary at the beginning of the season, lifted his Passing from strong to prolific and he now has 34k salary... Other skills did not change that much...