No, you're in the right tribe. It's just that people here are a little sketchy because someone in this ttribe recently had a pretty major accident, based, in part, on the advice they got here.

1) Like anything, the bigger the supply, the more the toy will run. Start with a little portable bottle for brazing torches and move up from there.
2) At least 3mm of aluminum and a good ball valve. Distance is functionally irrelevant; connectivity is king.
3) Got me. I'm a fan of copper, but I don't do separate accumulators.
4) Electric systems add several layers of problems:
. a) How do you keep the system charged?
. b) How do you ignite the poofer?
. c) what happens when your valve freezes? [notice, not "if"]
. d) shorts in the system plague electric systems.
. e) long arm manual valves are so much more reliable.

Also, check the legality of poofers on mobile vehicles wherever you plan on running these. Black rock has a 10' height limitation, California won't let you shoot liquid fuel, etc.

Thot I'd add a thought or two; by no means gospel, I'm just a guy who's built a few poofers and I haven't blown myself up yet.
1) Store-bought propane tank with new style threads
2) I keep the two near enough so that I can reach all valves without having to run back and forth. Re: valves: use Parker brand: they're the best and they're rated far higher than normal plumbing fittings. Use NO cast fittings; stick with machined fittings. I prefer brass over stainless because it's cheaper and easier to machine.
3) Black iron pipe? Maybe; just be sure you avoid brass pipe because, altho it looks pretty it's prone to cracking. Copper tube can crack too, if exposed to excessive flexing, but it's easy to anneal; not so brass. Seamless stainless is nice but it's *very* expensive. If you decide to go with stainless use tube, not pipe and use Swageloc fittings. Just a personal preference. Only reason I can think of to use it, tho, is for piping that's going to be in a direct fire path for loooong stretches of time; i.e. for superheaters in steam boiler fireboxes for instance.
4) Have a backup just in case...
--Glad you're a plumber; you'll get the hang of it quick enough. Re: pilot lights: I'd stay away from sparkers and stick with a fire pilot, using bronze wool around a perforated steel tube. It's more wind-resistant and the glow makes it easier to see if it's working.

>I'm a plumber with years on gas line,(this dose not make me a flame effects specialist by any means) understand the concepts written here, and will find the recorces to get the info I need to do this in a safe mannor. By no means, I will not "short cut" any knowlage I gain,
I respect the safty of others, and the addvice given to me.

While just being words, that makes me feel a lot differently. See, we've got this unspoken gentleman's agreement here that we don't give a full run-down on how to build a flame effect device. We'll answer specific questions, but if you say "hey, design my burning man project for me", you're going to get a "F-OFF" on two levels. One, I won't design your project, and two, holyhell the liability of such a thing.

Also, the XTREME PYRO name made me hesitant to take you seriously.

1) size type supply? That is wholly dependant on how often you want to empty/refill your accumulators. Also, keep in mind that larger tanks generally have less surface area, and are more prone to icing up.
2)Accumulators can be at the supply. the effects must be a specific distance from your storage tanks. How far the accumulators are from storage is how long it takes to refill them, how far from accumulator to outlet is how fast or slow it is going to release.
3) iron. For what? If anything is pressurized, it better f'in be scheduled or rated. enough said.
4) Asco Red Hats are pretty nice.

But really, I have to say, if you want to positively affect more people's lives, spend all this money on food and burn that propane to heat it. then stagger over to 2pir, Illumination Village, DSC, False Profit Labs, Controlled Burn, or any number of the other large fire thingies, get them to let you Push The Button, and make a lot of fire.