Choose Charmander (manip 15 DV Special)
Manip low Defense L4 Rattata or L3 Pikachu to kill for exp. (ideally with crit for 2HKO)
Skip first Bug Catcher
Fight second bug Catcher (Scratch Kakuna to death, get Ember for 2nd Weedle)
Ember+Scratch Weedle Guy
Normal Brock (finish 1 HPs with Scratch)
Skip Pewter Center
Save 1-4 Embers on Shorts Guy
(8 or 10 exp. short of L16 evolve)

Manip Clefairy
Manip flier at some point
Skip Paras/Sandshrew (just need Lapras)

Squirtle is still likely faster because of Lass strats on Route 3 and better late-game rival fights