GG Mariposa Plus & Gorilla…

The gorilla fabric will be able to resist abrasion and have a higher tear strength compared to the mariposa.

No pack, except for some dry bag designs used mostly in rafting/kayaking, can protect from water getting your stuff wet. Put a thick garbage bag in your pack before packing everything in it. Small items can also be put in ziplock bags.

I personally don't mess with any type of pack cover. They all leak to some degree and I find them to be a pain to deal with.

The gorilla is much smaller. Decide on how much space YOU need first which is a personal decision for each person. Everyones needs are slightly different.

According to the specs, your Nimbus Ozone is made out of 70D nylon, so that’s the same material as the Mariposa Plus.

The 70D isn’t fragile, but if you’re off trail a lot or rough with your stuff, the Gorilla might be a better choice, provided you can fit your gear in 2800cu in.

Get the smallest bag you can fit all your stuff in. Extra space is useless and makes it hard to compress and stabilize your load, consequently making it a less comfortable carry. You can use your sleeping bag unstuffed to fill a lot of space, but only so much. The Gorilla is almost too big for me when I don’t have to carry a bear cannister. I’ll be picking up a Murmur for those trips when they’re back in stock.

I’d look at the weight bearing guidelines as a absolute maximum only you have to for short periods, like at the start of a long trip, or on a really dry stretch of trail where you have to tote 4 liters of water. I’ve carried up to 32 lbs in my Gorilla on a two hour dayhike. It was okay, but I could see would have started to get uncomfortable. Ideal comfort range on the Gorilla is more like 25-30 lbs max. Of course 35lbs is heavy regardless of the bag. If you thought you’d be carrying that much regularly, you’d be better off with a heavier bag with a more robust frame, I think.