I went yesterday for the second time. Went as the ban ended in the summer and had a rare clear sunny day. Did the same route you are planning and while the climb was pretty straight forward I did find the descent pretty hard work. Didn’t flow enough for my liking and the constant techy drop offs took their toll. Wrists, hands and feet did ache lol.
Did llanberis up and down yesterday and the descent was right up my street. Exhausting but I loved every bit of it. Wouldn’t fancy rangers descent unless the rocks were nice and dry.
For reference it was dry at the bottom and 10deg c and drenching wet in the fog and 2 deg with a nasty wind chill at the top so make sure you are well prepared. I’d recommend a spare set of gloves for the descent as my water proofs were wet through by the top and if I hadn’t had a spare set it would have been a painfully cold descent.
Also take a few inner tubes, pinch flats have been unavoidable for me