Cheech I would think the Afghan would give you the best chance of success. The conditions you are describing happen here in Pa to some extent. I try to find stuff that finishes as close to Oct 1st as I can get.
There are some things you can do to improve conditions.
1. Maximize air circulation around the plant by trimming lower branches and some center branches before bud formation. Also cut surrounding weeds.
2. Plant in an area where you get morning sun right away. This way the dew and overnight rains get dried as quick as possible. If I have a choice between morning sun early and shadows after 5 PM or shadows morning and sun after 5 PM I always choose morning sun.
3. Preventative treatments such as aspirin water,
green cure and there is an organic treatment that eats mold (can't think of name right now) that you need to start using before the mold starts and during the rains when you can.
4. About September put a good layer of lime on top of the soil and around the plant. It can kill mold. Lots of molds are actually on the ground just waiting to spread somewhere.
5. Avoid planting under trees if you have a history of mold. Bird droppings and insect droppings are a major source of mold starting. It gets on your plant and it has mold spores in it or gives a nice medium for mold to start in.
Sometimes the conditions are such that you just can't pull a grow off outside. Last year was bud rot city in the Northeast and Mid Atlantic states. It sucks. Most years around here we get the cool, rainy weather at some point. It can be mid to late September and then often it gets sunnier and dry mid October on. That is really frustrating. Because you get some rot started, cut stuff to save it but then the last 2 weeks of October and 1st week of November are super nice and I am thinking "hell I coud have left stuff or if I knew this I could have planted a longer flowering sativa.
I don't haul dirt for most of my grows outside. I just dig up the soil and amend it with some lime if needed and use chemical ferts. It's hard enough doing an outdoor grow let alone making it organic. If you just do a few holes it can easily be done. If you do a a hundred guerilla holes it is not practical.
Michigan should have nice soil. Pennsylvania has great natural soil in most parts.
You are in a tough spot to do an outdoor grow though. You probably have lots of water vapor in the air from the lakes and you are a bit farther north.
Guerilla Gold and Guerilla Gold crosses might work. Danish Passion and lots of pure afghani are done before October.
That's the best I can do to help. Maybe some Michigan growers will stop in.
MOLD AND BUD ROT SUCKS ASS!!!!!!!!