1938 John Deere “D” help

New member here!
I’m just wondering if someone out there with experience working on the D could help me out with a couple things.

#1- what is the proper procedure for adjusting both drive chains and tightening them up? How tight/loose should they be?
#2- I use this as a fun pulling tractor, any tips or hints on things that could help me out? We pull for percent rather then distance.

Thanks in advance!