which lumber for sparse paneling in the garage

[Yrrol]

I've been out measuring in the garage now, going to put up more boards between the rafters...

The length varies between 225-240cm
The distance between rafters is 84-100cm

And I'm planning to do this myself but I'm not sure which lumber to purchase.

Since it's drywall that's going up, I should probably go with 30cm between each board.

But how thick and wide, and what type, should I buy for it to be both sturdy and affordable?

 

[Yrrol]

I received the wrong timber with my last purchase, can I use regular exterior house panel boards or will they buckle?

 

[cheetah1]

If it's not wider than that between the chairs, it should be okay, but the standard is otherwise 28x70. cc300 is normal as you say, though.

One can also (apparently) use plywood instead of glespanel.