This book has a whole section on shaping, proportions, checkering, etc. The finishing info is dated, but the rest is still valid ; https://www.amazon.com/NRA-Gunsmithing-Guide-Updated/dp/0935998470
I have the first edition of this book and it covers every aspect stock making. I have not seen this second edition, but it is likely as good or better : https://www.amazon.com/Gunsmithing-Projects-Second-Publishing-Company/dp/187935683X