Chain of Vapor and Null Rod

[Oath of Happy]

Ok, so I'm a little confused about Chain of vapor.  First I have a question, and then I'll present a situation to clarify what I'm asking.

Do the copies made by saccing lands use the stack and do players get priority in between the resolution of copeis?

From the way I thought of it, the sacraficing of lands and returning of permanents are all part of COV's resolution, so players don't get priority in between each permanent getting returned, just as if you play brainstorm with 0 cards in hand, you can't draw 3 cards off Brainstorm, play some of them at instant speed, and then do the put 2 on top of library part.  Am I correct about this?  Heres the example

I have Sol Ring and Darksteel Colossus in play and opponent has Null Rod.  I play Chain targetting Rod, my opponent returns rod, then sacs a land to make a copy targetting DarkSteel Colossus.

Question 1:  Can I counter his copy of Chain of Vapor?

Question 2:  Now that Null Rod is off the board, and the copy of COV is targetting DSC, can I tap Sol Ring for mana, return Darksteel Colossus, then sac a land and target my tapped Sol Ring?

Thanks in advanced

[LordHomerCat]

Think of it more like resolving a Tendrils than a Brainstorm.  When you resolve the first Chain of Vapor, you will bounce something then make the decision about whether to sac a land.  If you sac a land, you then place a whole new copy of Chain on the stack, with a new target.  Then, as you are finished with the original chain, it hits the yard.  Now, your stack has a copy of CoV on it, and we are basically back where we started.  Remember this copy is not actually played so it doesn't count for Storm and can't be Counterbalanced (for example), but it is still on the stack.  Now, active players gets priority again.  In your example, you would now be able to tap your Sol Ring and even play another spell with the Chain Copy still on the stack.  When you both pass priority, you will resolve the chain copy, choose to sac a land, and repeat the whole thing.  Each player has to get priority between resolving each copy (like a Storm spell, not like a brainstorm) so you can counter the second or third or fourth etc. copy.  In your example, you can counter the copy pointed at your DSC and end up with Sol Ring and DSC on your board vs. no Null Rod for him.

The key here is that Chain doesn't say to just repeat the process.  It specifically says to put a copy on the stack.  This means you finish resolving the original chain first, and then since you had to put a copy on the stack, you have to go through the normal priority passing thing again.

Short answer:

1 - Yes, you can.
2 - Yes, you can do this too.