Forend iron question

[Tom]

This may be simple to some, but I'm trying to do this right.
I'm fitting a forend to a different set of barrels. I can see how the iron wedges itself between the reciever and the stanchion soldered onto the barrels, but does not touch the barrel tubes at all.
Now add the wood. Should the wood have clearance on the tubes or should it rest on the tubes when installed ?
I am talking about a splinter forend.
Thanks for any advice, Tom