Honesthans, looking more closely at your choices I see some problems. The flashback arrestors you selected are size B and are too big to go on the end of your torch handle with A size fittings. This is not ideal for 3 reasons. First they put unneeded weight on the end of your torch. You could make that combination work with an A to B convertor but that would just add more weight and expense. And it is not as safe as putting flashback arrestors next to the regulators in case you accidentally cut the hose with your flame (or whatever) because there is nothing to then stop the fire from exploding your tank like a bomb. Remember that arrestors are location specific so the torch side arrestors you chose can only go next to a torch. You need a regulator side arrestor that has the male/female fittings reversed in relation to the only way it will let gas flow. I recommend small and light A size check valves on the end of your torch if you want maximum safety.
TM Technologies where you are buying your light hose has all the right equipment at similar prices to what you are paying through Amazon. The oxygen regulator you chose is designed for higher pressure applications and would make propanes flame adjustment difficult. It is much easier to light a propane flame under lower pressures like between 2 and 5 psi. A very slight turn on that Smith regulator sold on Amazon will change the pressure more than you would want (like eno said). This is what I suggest you get from TM: AWS-0217- Vic and AWS-0218-Vic oxygen and propane regulators for $87 each, AWS-0374 B size regulator flashback arrestors $34, AWS-0051-T 12.5’ T hose with a B fitting on one end and an A fitting on the other $18, AWS-0214 male A to male A adaptor $4.90, AWS-0052 Ultralight hose $45, AWS-0386 A size check valves $21. That is also the order you would put them on from the tanks to your torch handle.
My local welding supply store sells 80 CF tanks for $275 (the ones I use are bigger and cost more). You aren’t actually buying a specific tank that they refill each time, you are buying a tank that when empty you exchange for different full one. I pay just under $20 for a oxygen tank refill. The cost of a tank and regulator at my store are more than a refurbished oxygen concentrator from M&M Medical Repair. If you bought a smallish 40 CF tank for $175, they might be willing to let you buy a bigger tank for the difference in cost ($100 more) when you got tired of running to get refills. Policies between stores. This can keep your initial expenses down until you get more established. If you buy someone else’s tanks, your welding supply store has to approve they were inspected not that long ago that they can be put in their tank inventory. You would want to check with your local store 1st before buying something that they won’t refill.
I don’t have anything to urge about any of my suggestions but just trying to keep you from making money and time wasting mistakes by providing specific options I know will work together.