I haven't grown that particular variety but would think that 6-8 weeks in the fridge should be long enough. They might germinate while in the fridge so check the container every week or two. If you see that they have sprouted plant them immediately. If they don't germinate during stratification they should germinate fairly quickly once you plant them. A seed mat might help. You could also winter sow them or direct sow them now and they should sprout in the spring. For growing inside place your seed trays under the HID lights as soon as they are planted and make sure the soil remains moist. The HID lights should be a minimum of 4' away from your plants.
Karyn

oh boy.
A word of caution. Ok MANY words... I have tried over 1000 plants from seed. Physalis is without a double the most invasive, difficult to irradicate of all of them. A garden center near here prefaces their purchase by saying be sure to plant in a place where you can round-up or mow around it.
You can't contain them in a dug in pot as they will grow over also thru the drain holes. Worse than obediant plant to remove.

You can't tarp them to remove them quickly, as they will grow under the tarp. You can't round-up them to remove them, they just keep coming up. - you have to dig it all out including all the dirt and those things run underground for severla feet. I lost quite a bit of garden space for a year ....in 2 gardens. Never again.

Now- if you must.
They wintersow just fine. Poor lanterns the first year but more the second. Not pretty as the lanterns hide in the foliage. Better dried. I'm zone 5. Hope this helps.

Good luck!
Karen

I am in Zone 3 so they pretty much die off in the winter here. I only rent....hehe, but I really love these plants.....and for the first couple of years I am hoping to keep them in containers (because I rent...lol)

Dry shade holds them back a bit.

I'll never grow them again! I grew them 5yrs ago and every year since, i pull them up. They are very very invasive!

All i did was throw them ON the dirt and they grew.

As stated in the post or 2 above; the 1st year they dont look like anything. But the next summer and thereafter, you are just about stuck!(forever)

And they dont look all that great either!

Just my 2cents.