I have done 30 attempts now and have lost the initial battle in Bosnia every time except once. In that one success I had a Discipline adviser and got an event that gave me 10% morale. Then I barely won the battle, but then the Ottomans proceeded to siege down Albania before I could siege Hum (Skenderbeg has 0 siege).
In every battle I was parked in the mountains and the Bosnian general had anything from 0 to 3 shock. He always came in with a 3-1 advantage in men but I had between 4 and 8 modifier difference (5 from Skenderbeg + 3 from terrain - the opposing general).
I simply refuse to believe you won in all your 30 attempts. I will give this a 1 in 50 chance of succeeding.
There is no way to have more than the three starting regiments.
There is no way to get out to sea with more than 1 regiment.
Attacking Ragusa instead of Bosnia yielded the same results.
I have tried with a Discipline as well as a Morale adviser. Didn't help.
I have tried attacking the 6 Bosnian regiments in Bosnia so that the odds only were 1-2 but still got sniped every time.
Why are you parking anything in any mountain before the bosnian army has stack wiped?
I just tried it and it worked again without any advisors or events. But i noticed something that will make this even
easier... if you on 11th november scorch earth and start recruiting a merc infantry the Ottomans won't attack you until you have already gotten the merc inf and dowed Bosnia. So do exactly like this:
11th november
Assign Skanderbeg and recruit heir as general (maybe get lucky and get siege bonus on him)
Scorch earth
Recruit merc inf
Do not do anything with your diplomats yet
Unpause until you get your merc
DoW Bosnia (unpause one day)
Get military access from Serbia
Stack wipe Bosnia (you move your army straight to Bosna, hold shift and then click Travunia so it never stops at Bosna when you win the fight)
Merge armies so that your regular 3 regiments are left and disband merc. Make sure that while merging you got left 3 regiments, not 2.
Remove Skanderbeg from any army so he doesn't die from unlucky roll because he is commanding army (go to a Serbian province with him and quickly back without him).
Cancel MA with Serbia (to be able to loot provinces)
Siege Donji Kraji without general (heir if siege bonus)
With the very weak third regiment you got left you move it immediately to any province where Bosnia is currently recruiting regiment to stop the recruitment (
this is very crucial). Have this weak regiment stationed at Hum so you can quickly move it to Travunia or Bosna and so you see if recruitment is happening in Travunia. This weak regiment is also your "looter".