I have a HCIM
I quit playing it a while back, but at one point i was 10 ranks behind itam (13 v 23) on the HCIM boards

I have about 200m worth of stuff in the bank i could sell if i converted, and i dont think i would go back to it, but thats kinda a big choice. Also what could i do to farm GP (90+ all maxed combats 95 slayer) while playing my osrs account (need High intensity and low)

Are you asking if we think you should sell and convert?
Or are you asking us if we feel you should kill monsters on your hcim while afking osrs?

the 1st one
its like 2500fg worth of stuff and i dont THINK id ever go back

It's up to you really, if you have plans on never returning, then sure man.

For gp farming -
Vorkath
Money snake
Demonic gorillas
Slayer
Gwd