Nathan Foster
I think that's a really good idea Ben- 26", then cut down to 24" later if you don't like it.
Having said the above, the suppressor might make this a bit of an issue. You would want some meat at 26" before thread cutting. Can be a lot easier at 24". So you need to decide on whether you really want to fit the suppressor or experiment with the longer barrel, or fit a barrel with a bit of heft to it (e.g. True-Flite #2 contour barrel, specifically contoured to suit M14 thread at 26").
Just bear in mind, a #2 barrel in .25-06 is a bit heavier than your average rifle in a larger bore diameter. Don't know if you have ever handled a Sako Finnbear or Ruger semi varmint .25-06 but these were very hefty rifles between #2 and #3. So have a think about how far you want to walk with the rifle. Certainly stout and potentially accurate.
Then again- I don't know what thread is on your .25-08. It may be half inch / 12mm- not really my cup of tea.
Sako AV with 24" TF barrel, #3 contour fluted. The contour duplicates the original but is fluted. Not the lightest but very sturdy.