Yes, I had a spider mite problem on my indoor one for a while.
My soil mix is very much like yours MadPlanter, probably about hald sand/perlite, and the other half is regular potting soil (maybe even cactus soil in a couple of those)
I germinated mine in my aquarium converted to plant propagation chamber. 4 inches of water in the bottom and a platform above that to hold seedlings and rooting cuttings. There's a bubbler, small filter, and heater in the water. so it was very high in humidity, hanging in the top is a small PC case fan to circulate air. I threw a couple dozen seeds in a yogurt cup with a soil similar to what I described above. I was half assed about covering them and just sprinkled a little extra soil on top, some got covered, some were still exposed.
I had an excellent germination rate.. some damped off or died, but most lived to the point where I had to thin them out. Eventually when they started getting all tangled together I had to separate them. I waited too long I think because their roots were really tangled and I did a lot of damage while separating them and I lost quite a few more. So I was down to maybe 6-8 at that point.
I forget at what point I moved them out of the tank into normal temps and humidity. I suspect it was when I needed more room for germinating a bunch of caapi seeds. Some went to a window sill and others out to the greenhouse. I don't think I was gentle about adjusting them, though I do recall gradually adjusting the outdoor ones to sunlight. Up till that point they've only ever known LED light. They did pretty well in partial shade until they froze and I thought they had died for good, but I didn't throw them out. They were quick to show green again once we were out of the constant freezing temperatures.
Since then, they haven't grown much... just growing a bit, dying back, and resprouting from another spot. I kind of forgot about them and have been ignoring them for the most part. Now at the mention of growing P.harmala by one of our new members, I'm thinking about them again and wondering why such a seemingly hardy 1yr old plant is having a hard time getting any larger.