There isnít really a right answer.
Sure those measurements in thirds was a general rule but your taste buds are up to you.
It gets messy as most places may just do double shots as standard or are running 22g in which is more than you. So much is up to the basket size.
I normally have 18g in 34g out in a 180ml cup (so no split like yours)
My wife has it like you where itís split and I have that other half as an espresso to test the brew.
I would perhaps try not splitting and if too strong either have patience and you will become use to it or alternatively try a 20-22g basket and split.