Forget about my numbers “250” or “130”, those are just examples based on certain traffic mix. They do not apply to all networks.
The questions you are asking are very interesting and I have to let you find out by yourself because they would require too much work on my side. Let me just give you the limits you should not exceed in the BSC and in the cell (the limits below are = 60% of max capacity).
In B9:
max paging command per cell / hour = 118 000
max paging command per BSC G2 / hour = 252 000
max paging command per BSC Evolution / hour = 342 000
In B10, without mCCCH:
max paging command per cell / hour = 118 000
max paging command per BSC G2 / hour = 252 000
max paging command per BSC Evolution / hour = 432 000
For info, in B9 you can see the counter MC8a per hour, which is the number of PAGING COMMAND.
It is not very reliable, but it can give you a good estimation.
Don’t forget that all cells in a LAC will have to carry the same amount of paging commands !
And the BSC will have to process the total PAGING COMMANDS for all the LACs it is managing.