I’m happy to see you back to it. Growing as you know is extremely rewarding in many ways. You’ll probably find that soil growing is a bit easier too.
As far as the tent goes I always tell people to go with the biggest tent you can afford and fit in your space. It will save you from a future upgrade and you don’t have to fill it to grow a good group of plants either. If you have a tent that’s becoming to short by rapidly growing plants there are loads of great tutorials on low stress training. I personally train my plants even when height isn’t an issue. During the initial grows it may be worth taking ppm numbers down. Not as much for measurement numbers for the feed but measurement numbers for future grows. You can always look back and see what you did and at what times.
There are a lot of growers that have a good greenleaf schedule down and could be a good starting point.
In my opinion I think Ph is important too. The input ph does affect the final Ph. Some growers, myself included have a higher input which works out to a perfect Ph when nutrients are added. I don’t have to adjust but you and others may need to. I hope this helps!