UFH castellated panels for 100mm centres

[Post and beam]

Following the 'slow and low approach' to planning the UFH and Heat pump for my upcoming build i believe that close pipe centres at as low a temp as practical is the way to go.

So, if i go with 100mm centres i doubt that i can accurately( if at all) lay the pipes required to a neat pattern. Not without the castellated panels anyway. I priced these this morning and it looks like it might be about £1.5k just for these.

I understand that UFH installers are generally not keen on close pipe centres because it takes too long to lay. Does anyone know if this is actually true. Even if it is i think it might be better to just pay them what they need to spend the time to ensure a good job.