I gotta take issue with some of the comments re: using a silvia. They were brought to my attention by a prospective customer. I will state that I am (a native of Montreal, now in Los Angeles) in the coffee business full-time: Specifically selling and supporting espresso machines with precision temperature controls. Well over 750 units shipped in four + years, worldwide.
1) The stock Silvia is fine with a timer. But only for 2 or 3 hours in the cases of STOCK silvias.
2) Priming is NOT needed after making a cup.
3) If left on for more than an hour or so the wide swings in idle temp. of stock silvias, will cause the boiler to slowly empty into the water reservoir. This is not good and causes stress on the boiler. But then, I have serviced stock silvias that were over 9 years old!
4) Heating something up is faster than cooling it off -- a basic law of physics. Shots pulled BEFORE steaming will be closer to accurate brew temps than those pulled after. I know, having the shot sit for 90 sec is not the best thing, but far better than cooking the coffee with an overheated brew boiler and brew head.
5) Heat up a Silvia for a bare minimum of 20 to 30 minutes, no less. Use advance planning or a TIMER.