Trouble is, it's too warm still for a Tool when doing high output activities.
I have an old N2S Gore Complete that I've worn from 30C to zero. When it's hot, the sleeves come off, when it's less than about 8C, I use a synthetic base. For me, Merino is shite as it takes ages to dry (from sweat or sky juice) and goes clammy and saggy and chills you.
Colder than about zero (or just above), I use a Tool. When it's very cold, I wear a synthetic base with it.
For either when it's cold, I take a pertex windproof and use this to avoid getting cold during/immediately after stops.
Softshells are OK but they're really a solution looking for a problem as were their predecessors, the Buffalo 'system'....