I am analysing Air cooler inlet line (350F temp) of 42" NB with 24 nos nozzle(12 tube bundle). each cooler header( inlet/outlet, even pass) has supported at 4 points of it's 4 corners with slide pad.
Vendor allowed gap in transvers direction (X) is 2.5" both sides ane
longitudinal movement (Z) of tube bundle is limited to 1/8" by the support at header box.

I am supposed to deliver the final report of this system and i found 2 different approach for analysis.
please suggest me the pactrical/justified approach...

Approach-1

Model the piping and header box (rigid) not tube bundle. End supports of each header is Y,X with 2.5" gap, Z with 1/8" Gap,RZ and RX with 0.1 friction coeff.Ry is free.
1/4 th of the weight of tube bundile has been imposed on the header box near to the support.

System is safe fron nozzle load and moovement of cooler also with the limit.This is analysed at the prelemenery stage and load to structure has been forwarded.

Approach-2

I model (in addition) the tube bundle and rare header with their weight and place 4 supports at proper location per vendor drg. with fric. coeff 0.1 with same supporting as approach-1 (Z is free at the rare end header).
Now the transverse moovement of tube bundle is controled by the frictional force at 4 suooprts and huge moment is accumulating in individual nozzle.
To reduce load we need to modify the layout ( need more flexibility in between piping header to nozzle) , but our design team is not ready to change the IFC lines of that big size. My Stress supervisor also agree with me but, he also telling that it will not effect the system in pactrical. but he did not able to explain how nozzle load will reduce in the field.

I want to know should i be strong on my point of view ?
or let the system go for fabrication which not giving staisfactory result to me? need urjent help.