Different base sizes

Sorry for keeping to ask this all the time, but this time it's not about units but about tokens.
Is it said in any part of the BRB what size the mission objectives have to be? I see a lot of people use regular 25mm bases, but I was thinking of using 40mm bases for the up to five small objectives, and 60mm bases for the two 'home objectives'. Yay? Nay?

And then of course pain tokens. The size of them is not ruled anywhere because basically they don't affect the game at all but rather work as reminders for the players, yes? That being said, what is more common, 25mm or 40mm?

Thanks!

I guess both are matter of agreement with enemy. One time I had few Imperial bastions as center objective and "power plants" as home objectives (scenario allowed any unit in reserves to be deployed without scatter within 6" from bastion if You captured it while enemy did not captured Your power plant).

Only thing I found about objective size is on page 91, which says objectives can have any size.

BRB p.91 wrote:

As different objectives vary in shape
and size, it is important to agree at the beginning of
the game exactly where this distance will be
measured from.

Standard bases seem common, but you can take whatever you want.
In my group for example, we use tokens to represent different objectives, in or on terrain, or just terrain pieces, as they are.

For example we have a 40mm base nestled with antennas and satelite dishes that can be placed on any building to represent a comunications relay, but it couldn't be placed on the ground.
But we use exeptionally many buildings, so it is very uncommon to have any objectives outside of buildings.

I just read that 40mm seems to be standard for tournaments and events. Would it be 'modelling for advantage' though, if I made at least the Capture and Control objectives 60mm? So many possibilities to build a nice objective!

And how about the Pain Tokens. Any opinions?

I use 25mm bases for pain tokens. I have a spike in the middle over which I slide space marine helmets to represent each pain token the unit gains. Simple and efective.