Four minute fix and you're a legend forever, kids remember that stuff.

Two shorter ones joined always sag in the middle on 8 foot rips.

Same exact thing happened to me with those little tubes turning into solid bricks in my gear bin. I thinned mine with mineral spirits too and used an old spray bottle from the dollar store, worked like a charm on the whole rainfly in one go. One tip from my own mess up, do it outside on a windy day because that smell will hang around your garage for days (ask me how I know). Just go light on the first pass and hit the seams twice, thin coats beat one heavy soak every time. Nancy you will not regret grabbing that sprayer, wish I had thought of it years ago instead of wrecking my back on the picnic table.