You should have posted this in the MFPro section, not X-feeder.
But using Martingale at lay prices around 4.0 or higher sounds very risky to me. I would rather lay the away team at much lower odds like 1.5 - 2.5. Home advantage is always strong even at those prices and you still win if its a draw.
If laying the HT 0-0 score then a good strategy is to back the 0-0 FT score to cover the potential loss on the HT score. If it is 0-0 at HT you can trade out the FT score for a much smaller overall loss. If you can hold on till about 55-60 min, you should be able to trade out and break even. Match and price selection is important for this to work effectively.