Anyone have experience of the Edinburgh-Thurso rolling stock?

We're off to Orkney for a long weekend at the end of April, and need to decide on how many bikes we take...

* Outbound

Edinburgh-Perth no cycle reservations possible. Any idea what cycle space is available here? Is it the standard commuter arrangement (Carriages with bar officially taking two bikes?)

Perth-Inverness two cycle reservations possible. Are we likely to be able to squeeze more in without reservations?

Inverness-Thurso four cycle reservations possible

* Return

Thurso-Inverness four cycle reservations possible

Inverness-Edinburgh two cycle reservations possible

We'd like to get 5 bikes on board, but one can be a folder, and two are children's bicycles with small(er) frames.

I think for each train we'll be boarding at the start of the line, and disembarking at the terminus, so the odds are pretty much in our favour...

Unfortunately we don't have the option of simply getting the next train at any point, given the length of the journey, so that's not in our favour!

Robert