Plz help gdp

My GDP has got quite tall is now 24” from soil surface to top leaves. My plants are all in 10 gal fabric pots on elevators so from bottom of tent to tallest plant tops is 38”. In a 48”(W)x48”(L)x80”(H). When should i top? When should i prune and can anyone point me in the right direction on where they learned to trim? Link to a YouTube vid or article to read u recommend? Ive never trimmer or topped at all yet whole grow. They are 5-6 weeks into veg. i shoulda grow journaled better.

OUTLINE OF MY RUN:

1. Indoor or outdoor? - size of grow? A: Indoor 48x48x80” tent 5 plants only.
2. Origin of seeds? A: Gdp, harlequin, Pineapple Express #2, platinum og.
3. Regular, feminized, or autoflower? A: Fems. photoperiods 18/6.
4. Origin of water. PH, EC/TDS of source water? A: tap. Dechlorinated in 5 gal bucket w air stone 24/7. 8.4tap ph before gh ph down to 6.5
5. PH and TDS/EC of if mixed solution? 6.5 gh ph down used.
6. Grow method? Soil, Soil-less, Coco, Hydro, Aquaponics. Please explain. A: soil. FF oceanforest & happyfrog 50/50 mix w 5% coco added also a bit more of perlite and wormcastings
7. Nutrients or fertilizer system used. A: Gaia green 444&284 50/50mix only 1 tbsp each & bit of wormcastings.
8. What typr of lighting are you using? LED, HID (MH, CMH, HPS), or Fluorescents? Please elaborate. A: spiderfarmer sf4000 40% 24ish” 132watts above tops of plants.
9. What are the temps in your growspce? Day / Night? A: 68-70 night. 71-77 day drafts make this hard to control.
10. What is the RH = relative humidity in your growspace? Day / Night?26-32
11. AC, Humidifier, De-humidifier?
12. Do you have a Ventilation system? Size? 4", 6"?
13. Co2 Yes / No? A: no.
14. How long have you been growing? A: First timer. On week 4 veg.
15. What budget have you set in order to grow successfully? A: Cheap as possible for essentials only w longevity.