What's your opinion on pruning off the 5th no...

Nothing wrong with topping at the 5th node. Now with that said 4in. to take of most likey will add some stress it is doable tho especially when they are healthy like your plants look. I have done it before with mixed results some plants had no problem some got stressed but made it fine. You can always take like the top 2in off and do some HST or LST to keep the canopy even just be careful to not snap anything. or you could just try the LST or HST a not top. A lot of it is personal preference. like for example I prefer to do LST or HST instead of keep topping. Once have already topped a plant once or twice i usually don't like to top more than twice. so that's why I prefer to do bending an what not after the topping if i still need to control the canopy height or fill in spaces. another thing you can try to slow down the vertical growth is to give the top of the stem a little pinch not enough to damage the skin of the plant but just enough to where it squishes the stem a tiny bit and yes it can stress it out a lil but no more than topping if done right. the idea behind it is that once you do it the plant will focus on healing that spot instead of vertical growth and most of the time the stem grows back thicker/tougher than before. good luck!. Hope this helps and if you got any other ?'s just shoot me a message👍 Happy Growing HoffGuyy