When do i switch the Light cycle

[Swampzillah]

Planted this on 10/1/20 and have it on 16 hra light 8 hours dark. When should inswotch to 12grs light and 12 hrs dark? Also a friend suggested i repot to a 5 gallon pot. Thank you in advance.

 

[ws2910]

Novice here - repot yes. I searched high & low with the same ?. Best info I found is, worst case your plant could double in size so flip when it is at 1/2 height of your grow space minus 18" (light at the top)