I used to top feed mine throughout veg 3 times a day, I do the same for the first week in the UC. I kept my water level 1-2in below the net pots for about 3-4 days of that week, until my roots popped and made its way towards the UC stew, then I raised to the bottom of the pots. For the last week before they hit the UC and the first week in I try not to hit the cubes while watering. This worked very well and I really had no complaints other than having to use my room to veg instead as a straight flower room, as I always needed that week for my roots to become UC style roots. My plants continued to grow as they did when I was top feeding and after 4-6 days they were at UC growth speed.
For my last two runs I have been running bubble trays. They work great, but you still will have the sane entry into the tray as you will the UC. Beating that stall goes for the tray just as it does the UC. One thing I did with my bubble trays lid is instead of drilling holes for the net pots I made ny lids with cut out rows so I can keep my net pots in my lid. This helps in a couple ways, I don't have to squeeze roots out of a hole and back into the hole in the lid and I also use the lids to cover each cut row keeping light out but a simple lift or slide to check roots. Depending on what size I want to veg tells me how many per tray. I start out with 16, four rows of four, while clones. I only need 12 so by the end I run two tray with 6 in each, but grown big for trees. This allows me to bypass vegging in the UC , which also saves me on the amount of lighting used in veg. I still will veg a week in the UC before flower but that will only be to get them used to lighting and train for space. I really like these set ups but it does all come down to having enough space to run a table or two while your UC is steadily making flowers.
