Soil questions / first grow / guerilla

Hi, I made this thread earlier https://www.rollitup.org/t/first-grow-guerilla-grow-need-help-with-soil-related-questions.1050318/#post-16247252 and explained my situation in depth but couldn't get exact answers to my questions. So I'm making a TLDR version here, if you could answer them would be much help. If you could read the other thread it would be huge help.

I want to grow a guerilla for some reasons and I want to use the natural soil in there as much as possible. I'll be planting both Autos and Photoperiods.
1. I believe that the soil is around %65 sand %20 silt and %15 clay. I live in a mediterranean city, summer is dry season here. How can I adjust soil the hold most water without affecting the drainage? Is perlite a good solution or there are other ways? How much perlite is too much perlite? etc.
2. Soil ph is probably around 5.30 - 5.70. Is agricultural lime good solution to raise ph? I plan to plant late April, so I have around 3 weeks. Should I directly mix the lime with soil?
3. I've cut some trees and bushes to make space. But derooting is a hassle. Do leftover roots affect cannabis plants? How long do they live anyway with the top of the tree being cut.

Also bonus question: How can I test the ph myself without buying expensive equipment? https://www.rollitup.org/t/how-to-measure-the-ph-of-your-soils-runoff.8595/ Is this water runoff test accurate?

1) peat moss is better than perlite at water retention.go easy on perlite if its sandy soil. You already have drainage. You get better at soil mixes after you mess with them long enough.
2) less variables the better until you master the soil, no lime this first time.
3) cut roots wont mess with grow. Trees can live another 30yrs with a top cut, i mean how big a tree we talking. You know how hard it is to kill a tree?
4) dont worry about ph, rain ever get ph'd by god? You can test the soil ph with a quick and dirty test. Honestly for outdoor grows this will ballpark your ph then go from there.no reactions? Dont fk with the soil ph.