Allan
This is the type of burner I have used for years:
http://www.amazon.com/Stansport-Triple-Burner-Stove-30x11-Inch/dp/B003IUJST8
45000 btu with all 3 burners on and runs from a 20# tank Get you to 200 f in about 20 min. Crank the burners up so the flame is just licking from under the tank and watch the temp, when you get to 190 turn the burners down to just a blue flame with a lick of white and it will hold perfectly.
I have them back to back on a stand so you can go from park to rinse. End to end would be better if you have the room, less drip and sizzle. Your tanks will fit fine.
Yes, you should filter your solution when it gets grungy and clean the tank of the crystalline buildup when you filter the solution. I also add more concentrate when I add more water. I might be wasting a little concentrate but don't have to re-due parts very often if ever.
If your tank is clean on the bottom laying a part in there is not a problem, just rotate it every 3-4 min or so or lean it on an edge. For small parts use a SS basket or a chrome plated fryer basket and shake the basket every few minutes.
Definitely use Alum oxide (garnet) the brown stuff, stay away from anything Black and watch the nozzle on the gun they do wear out and don't blast well then. Wear a dust mask if you don't have a commercial dust collector.
DO NOT try to park on rainy or high humidity days, the parts will start to micro surface rust while you are dusting them off from the blast cabinet and you will get poor results.
I wipe down the parts with acetone after blowing the dust off before going in the park tank. Just make sure you are in a well ventilated area and have no open flame in the area.
I use a military general purpose light oil mixed with mineral spirits to bath the finished parts, hell for that matter you could use motor oil but cut it with min spirits until its about water thin.
Just my 2 cents
Troy