I have an EA that I'd like to modify so as to make it a grid/martingale trader.

The EA modification should be as follows;

Under parameters, there is 'lot size'. I want an extra parameter called 'lot mode'. If 'lot mode' is manual, then the Ea shall
use the lot size selected by the trader. If the 'lot mode' is auto, the EA shall select lot sizes in the following manner,
if initial lot size is 0.1 and it is a loss, then next lot size shall be the NEXT AVAILABLE lot size i.e 0.11. Thereafter, if
0.11 is a loss then for the next trade, the EA shall double 0.11 i.e new lot size shall be 0.11x2=0.22. if 0.22 is a loss 
then for the next trade, the EA shall double 0.22 i.e new lot size shall be 0.22x2=0.44. When there is a profit trade then 
EA shall open new trade using initial lot size. So;

1st trade- initial lot size
2nd trade- next available lot size
all other trades- last loss trade lot sizeX2
Trade after profit trade- initial lot size