Side project single cola flower clone

She’s on week 6 GSC clone I cut in flower How can I get this tiny plant as fat as possible? She’s 1 liter pot fox farm organic mushroom compost castings been feeding advance 3 part voodoo juice b52 big bud still can’t get it swell up not worry about smoke quality at all just something to do

Your well into flower. Feed as you should and just stick to the plan.

Fat colas are in part down to internode spacing, which can be the genetics but is also dictated by the spectrum you veg with.
Its too late in the game to change its structure , but the buds will still fill out. You wont get a pop botte width cola though.