On the temp front there are two extremes on Alfa cooling.
1) a shot stat which keeps the engine too cold. Rarely would pass the first quarter mark on the dial. New stat solves it.
2) Knackered radiator. Shown by a high temperature, even with the cooling fans running.
Yours sounds about right. The needle hovers around just in front of the 90 mark, but in traffic, creeps up and down.
That's fine. As long as the fans kick in and the temp goes down, all is well.
Also, the temperature gauge in 156 is notoriously inaccurate. Plug in proper diagnostic tools and you get a very different temp.
On the diagnostics front. PC based Fiat Ecu Scan, now Multi Ecu Scan is fairly fully functioned as a free download. The full version adds some nifty additional features for about £50 a year. Uses standard obd cables made for vag com software.