According to that S19j @ $300 will ROI in 75 days if mining 24/7 but since I'm only mining 1/3 of the day its more like 225 days.
How long will an $4000 S21 take to ROI and how many S19 can I buy for $4000?
I'm looking at this from a totally different angle.
Also this is more of a, can it be done project, I'm not expecting to get rich but if it can make profit I know I'm on to something interesting.
I think you're counting the payback incorrectly. You only count the cost of asics, but do not count the cost of investment in solar panels and equipment.
In 225 days you will have recouped your investment in the asics, but what value will those asics have in 225 days?
As an option for gaining experience it's a good idea, but investing in such equipment is definitely not about business.