Refitting dash - blower outlet foam gaskets

[sweetaswesty]

I wasn't sure whether to post this under body or electrical so apologies if I made the wrong choice.
I'm refitting the dash and there are these thick foam gaskets that are sandwiched between the dash and the two heater blower outlets that exit directly out of the top of the dash and I'm wondering whether they should be (a) taped/ glued/ fitted to the dash or (b) to the heater blower outlets before I refit the dash.
Any thoughts or advice? I'm planning to fix them to the heater blower outlets with double sided tape unless someone knows a better way?
Thanks!
This is what they look like and where they go:

[Stesaw]

Double sided tape is what I used. Should be fine at that once the dash is back on.

 

[sweetaswesty]

Thanks that's great!