Return measurement

["Michael Stewart" <michaelstewart@xxxxxxxxxxxxx>]

If your futures system trades a variable number of contracts how can you
fairly estimate the rate of return - would/could it be a) P&L / Total
account size for the period or b) the sum of P&L's for each trade / account
size for each trade or c) P&L / Average account size for the period

Whilst on the subject of 'return' - are there any seasoned traders who maybe
happy to share their own performance objectives/results  - return for an
'average' month for example as a return on initial margin (as return on
account size can be so misleading).

Thanks

Michael Stewart