I've just gone through the same dilemma.
I would recommend you put a 2 degree side bevel on them. 3 might work a little better, but 2 is enough imho, and it will wear better.
You certainly don't need any more than 1 degree base bevel. If the ski's are really old, they are likely flat. Putting a 0.5 degree base bevel on them will make them easier to skid and pivot, if that's what you like to do. You could always try them flat first, and then go to 0.5 if you find they rail too much for your liking, and then go to 1 degree if needs be. You will be wasting more metal if you try to get them back down to a lower angle having gone too far.
As to "detuning", let me tell you my experience. I had never heard of this until this year. I bought an old pair of slalom race skis (190 cm Fischer RC4 Vacuum technique SLS) at a yard sale for next to nothing, and brought them into my local ski shop for a tune up. I had been skiing exclusively on my SG racing skis for the longest time, and had been itching to get a ski with a shorter turning radius, but somehow could never quite justify the expense.
I only got the $30 dollar tune, not the $50 race tune. I wanted to try them out before springing for new bindings or investing a lot of money.
At the first opportunity I tried them out. It was a very icy day, and I was very disappointed with the skis performance. I had expected slalom skis to be better at making short turns. In fact I found that they were fairly good at making skidded turns, but in order to carve I had to be going fast, and even then they would only carve medium-long turns. When I got home I closely inspected them, and was furious at the ski shop. They had only sharpened the mid section of the ski, leaving two thirds of the ski dull! With other shops and my other skis (the SG racing skis), I had always been very specific in my tuning instructions "razor sharp tip-to-tail". Later I found out it was common practice among many shops to keep the tip and tail dull. It seems that the majority of skiers do the twist to point their skis where they want to go, and prefer to skid turns instead of carve them. This was news to me, as I learned to ski by imitating DH racers who always tried to get as little skidding as possible in order to maximize their speed. To me, the skis in this "detuned" condition were rubbish.
I bought a couple of files, and a two degree edge guide. I spent hours filing them the night before I tried them again; a lot of sidewall had to come off from the tips, and I didn't have a sidewall planer.
With a two degree side bevel along the entire edge, the skis performed like what I expected from racing slalom skis. They were able to carve short turns, but being very stiff, it took a lot of effort. The amount of effort needed to initiate a short turn was high, and the difference in input required for a sharp turn and a very sharp turn was minimal (to be expected I suppose since centripetal acceleration and hence force varies as 1/radius I must have been on the steep asymtotic part of the curve). They still skidded long radius turns unless speed was very high, but that's allowed. ONe thing I definately noticed, skiing these back to back with an equipe SC10 an SX11 and a B1, was that I could relax and watch the scenery on the other skis, but on these skis I had to be alert as any slight pressuring of the edges caused an immediate tracking of the ski in which ever direction the edge dictated. It was also more difficult to put usefull force on the inside ski without having it want to turn sharper than the outside ski.
A gentleman sharing a lift with me mentioned that he detuned the tip and tail and pointed to a spot only a few (3-5) cm behind where the ski contacted the snow, saying from that point forward they should be dull. This leaves significantly more sharp edge than the shop had left. I am currently wondering if I were to detune only that tiny bit of the ski, would they still carve as well when pressed into it without being so demanding at other times. Unfortunately I'm donating these skis to the Cancer fundraiser garage sale, having bought a new pair of RC4 SCs, so I guess I won't find out soon.