I ran into the exact same issue. I had a tent that I was going to scrog. I can only access the tent from the front because it is in a corner. As a first timer, I decided to skip the scrog net this time around.
I ended up buying a 3x3 drain tray for my 4x4 tent. I have 4, 7 Gal pots in it.
I made this DIY watering wand system to allow me to easily reach the back of the tent.
ECO 396 submersible pump
1/2 inch tubing
Ball valve - home depot
Flexible end - home depot - just randomly found this on a shelf for 2$ and decided to try it. it allows me to point it around for a bit more control.
I usually use around 2.5 gallons on these 4 plants (20 days into flower now, they are drinking more and more each time). I mix my nutes, then transfer it all into a 4 gal bucket with the pump in the bottom. On the tube end, I have the ball valve closed. Plug in pump, get myself into the watering position, then use the ball valve to adjust the flow with one hand.
This works fairly well for me. The major draw back for me is that the pump need water to pump, so its hard to get all of your water out of the container and to your plants, there will be some left over that the pump just can't get out. I overcome this by using a bit of extra water now. Initially when I noticed this problem I would just water the hardest to reach plants first, then when the pump stopped it was generally easy to just use a solo cup to add the remaining water to the last plant (in front).
I suck up the water drain with the wet/dry vac in that pic (also Home Depot), then towel/sponge up ALL water. Don't want to take any chances with bugs breeding or being attracted.