What's some recommended settings I could try to run this game optimally?

My hardware:
MOBO: Gryphon z97
GPU: Nvidia GTX 970
CPU: Intel Core i5 4670K 3.4GHz
RAM: Corsair 8GB DDR3 1600MHz
OS: Windows 7 Pro 64-bit

My native resolution is full HD so I would like to run it with that but preferably with either hq2x or hq3x depending on stability, I'm not sure which is one to go with. I'm using the forced parameter.

Also, I read there's issues regarding multi-core but I couldn't get imagecfg to work dosbox to automatically start it with one core. Mayube this can be done directly in Dosbox configuration, if so how?

The main issue, like all other dosbox games or those that run with DDraw, is that my mouse is typically very slow and if I move it quickly, the game engine slows down even further (usually music/sound too).

Sound/music is also cracking.

Yes, the sound is terrible in GOGs version but otherwise the game works fine. There are several threads in this subforum which already discuss DOSBox settings in detail, have you looked those over.
In Windows mouse settings, you should turn 'enhance mouse precision' (exact wording in English unknown) OFF and leave/set the speed setting at default = middle.
Sorry, that is all I have time now to help you with.

I have but I figure if someone had a similar hardware set up as me I could easily try their solution (the settings people mention in this forum lack hardware information).

Anyway, I changed the cycles from auto to 50000 and lowered it but then the game started to add delays so I increased it to 75000. I haven't really played anything, I'm going try more later but it seems to work now, both performance wise and music seems fine (excluding main menu).

I still would like to force single core for dosbox if it's possible.