Rafi wrote re: Merino shirts, "However, it's a bit too hot for temperatures in the 80s or more. I'd like to find a lighter weight merino short sleeve shirt for those situations. Are there are (non super tight athletic fit type) merino shirts @ say 120 weight?"
The looser the better when it comes to hot weather clothing. So far, nothing works better for keeping me cool for hot weather backpacking than my oversized and airy, thin 100% Linen button down shirts. Linen dries quite fast for a natural, absorbent type material--this is mainly because it's usually made thin, and because it's fibers are hollow and tubular in nature--so it will feel drier and cooler faster than a lot of other natural, absorbent type fabrics.
I find Merino, and Merino-synthetic blends to be much better for cooler to cold weather. But if you like the odor controlling properties of Merino and high Merino blends, you would also really like Linen too--they both are some of the best out there. It would be nice if they made a Linen-Nylon blend shirt to reduce the weight some, but i have yet to see such blends, even in fabrics sold by yard--i would make my own shirts if i could find even that.
You can often find pure linen shirts in good shape at thrift stores. The other benefit of thin Linen over thin Merino is that the Linen will last much longer on average--very high tensile strength compared to Merino. Merino and wool in general CAN be tough, when thicker, not treated to reduce shrinking and felting, and especially if actually deliberately felted some. The fibers via the scales will lock together creating more strength and durability than it would have normally. But a lot of expensive, sport wear and thinner merino shirts, etc, are treated now to either remove the scales or to fill them in, reducing those effects (shrinking and felting).