Ask HN: Bootstrapping with 2 founders

Hi HN. My partner and I have a Delaware C Corp all formed and are getting ready to do our initial investment. We want to maintain a 50/50 equity split, but I want to put in $1k in a lump sum and he wants to put in $8k in 4 installments over the next three months. What is the best way to arrange all of this investment to lower complication and tax burden? Thanks!