Your question may be closed because it’s actually not a question. I would like to use this space to give you a few comments that won’t fit in comments. I have a hydronic radiant heat system, some in concrete, some under a wood frame floor.
Read up on the short life of cast iron pumps and accessories such as microbubble separators if you use regular plumbing PEX instead of oxygen barrier PEX. If you use regular PEX, you’ll need bronze or $tainle$$ pumps and brass fittings.
You haven’t said so, but I hope you plan to use adequate insulation under your 8-inch slab so you’re not warming the earth as much as your living space. Also consider insulating your foundation down to a depth of 4 feet to prevent cold soaking of the earth under your slab.
In my opinion, don’t make yourself crazy with close spacing of the PEX near windows and such. Radiant heat is diffuse, and I would challenge anyone to detect a difference in comfort near a window based on PEX spacing in this portion of slab vs that portion. Radiant keeps the entire room at the same temperature.
Forget clock thermostats. Forget smart thermostats. Forget IOT thermostats. You will set a dumb thermostat to your comfort level in the fall and you will leave it at that setting 24x7 until spring. An 8-inch slab will take at least a day to reach operating temperature and come into equilibrium with the room temperature. Setting back the thermostat at night will be pointless, since the room temperature won’t start dropping for several hours. If it manages to drop at all by morning, it will take all of the next day to get back up to your comfort level. So go into this knowing that your fuel bill will reflect 24x7 heating with no setback. (If this is not acceptable, skip the radiant and use hydronic baseboards instead.)
Will you ever want to drill into your concrete slab? Before you pour concrete, take photos from all angles and make a map of your PEX lines with accurate measurements.
And good luck!
EDIT: Some additional thoughts
Decide up front how you’re going to control the radiant water temperature, especially if your boiler is also making domestic hot water. Any boiler can produce boiling hot water, but you’ll want circulating water in the 125F range, plus or minus. Super hot water would crack your slab. Will you use a thermostatic mixing valve (prone to sticking) and mix boiler hot water with returning cool water? Use an indirect water heater (decent temperature control) to feed circulating water and serve as a heat reservoir? Use a buffer tank with its own aquastat (poor temperature control but an excellent air separator)? My boiler supplies baseboard heat, radiant heat and domestic hot water, so I use a buffer tank and an electric servo mixing valve for radiant water. Works great.
Your boiler ideally should be capable of modulating its output from 100% down to 10%. When your total system is running at equilibrium, it doesn’t take a lot of heat to raise the temperature of returning water at 110F back up to 125F. If the boiler only runs at full output, it will short-cycle.
Don’t oversize your boiler. That would also lead to short cycling. Suppose you have an oversized 150K BTU boiler that can modulate down to 10% output – 15K BTU -- but the building needs only 8K BTU to maintain comfort in mild weather? It will short-cycle. A buffer tank would lengthen the cycle but the boiler would still start and stop far more than it would if properly sized.
You may find that you need to raise the temperature of circulating water a few degrees during extreme cold weather. Boilers with outdoor temperature sensors can do that automatically, and so can electric servo mixing valves if so equipped. Thermostatic (wax capsule) mixing valves can’t sense outdoor temperature.
