[Gooserider]

Pressure is NOT an issue, unless you are doing a really sloppy job on the plumbing... I forget the exact specs offhand, but a Danner pump is only good for about 10 feet of water head pressure. This translates to about 5 PSI. The radiator is probably the weakest commercial component in your proposed system, and it's tested at 25 PSI.

(Minor rad selection hint - if you can, get a single pass unit, not a dual pass, it will give much lower flow resistance)

Your proposed system sounds pretty good overall, with the possible exception of the tupperware res. I would want something a bit more sturdy, though I've seen people successfully use stuff that I wouldn't touch. (MY res will be made out of PVC pipe...)

See the poll and survey I did a while back on WC disasters (don't have the link handy) and notice that nearly all errors trace back to 'user error' at some level.

If you make sure you know what you are doing in terms of hooking up plumbing fittings, you shouldn't have a problem. (Note, Silicone is NOT an optimal approach, try teflon tape and plumbers dope on threaded fittings.) Remember that if a connection is not mechanically sound, no amount of externally applied goop will make it long term leakproof.

Good Luck,

Gooserider.