G'day Jack,
I haven't much of a maths brain so I use Dutch Book software (free).
which appears to allow for more than one saver.
Using your example I put in
#1 - 4.60 (saver)
#2 - 5.00 (saver)
#3 - 4.00
#4 - 6.50
Bet amount $50 and the calculation it gave me was -
#/Outlay/Return/Profit :
#1/$11/$50/0
#2/$10/$50/0
#3/$18/$72/$22
#4/$11/$72/$22
I find this the easy (albeit lazy) way to do it - but I need my computer.

Cheers......Mancunian