Nice one Mate!
Normally casting forward and fishing from about 2 o'clock to 5 o'clock.
Jig head weight is dictated by depth and speed of drift...You want to get the lure to the bottom by at least kinda 3 - 4 o'clock or you need a heavier jig..
Remember that as it goes through the arc and you work the jig and wind a little the lure will be working back to the boat a bit but kinda from the side some not straight back from the bow.
Am I making any sense here guys?
I would guess that maybe just maybe you were getting fish on the tow because the boats movement was imparting action on the jig by towing it against the current/movement.
When casting forward it is up to you to impart the wounded baitfish movement to your lure.
Sorry if you are already doing this and I am way off!
Naturally if you cast forward and don't work it properly it will be a pretty drab presentation in terms of exciting bites.
That said there is a happy medium to discover, there can very quickly be to much movement of the lure..
You will crack it no problem.
Also I have seen days when out the back is where it's at so go try again soon.