Personally I'd spend as little as possible on bench PSUs, and more on other test equipment. And you
will find you need more equipment
If your circuit will have a life "away from the bench", then it will need its own stand-alone PSU - so why not simply use that stand-alone PSU during testing instead of the bench PSU?
I wouldn't recommend building your own PSU, because
when something goes wrong
two circuits will suffer. The reason so many 60s and 70s power supplies were so trouble-prone is that often the PSU design was given to the newest least experienced engineer
I strongly recommend a PSU where each rail's voltage and current limit can be set independently of the others.
Apart from that, you need to define some of
your "use cases", so that you will be able to work out what's important for you.
You will need to define the minimum acceptable voltage and current for your purposes. If all outputs are floating then you can put them in series to get a higher voltage, e.g. 2*0->30V = 1*1->0-60V.
You will need to define whether you have integral meters or rely on front panel knobs plus external meters, whether one meter for voltage and one for current or one meter switchable between voltage and current, analogue or digital. In my experience it is sufficient to set the voltage, and then to continuously monitor the current. If accuracy is important, you will need to use an external meter anyway.
You will need to define whether the voltage/current controls need to be analogue or digital. There are advantages and disadvantages to each, and both are usable. Generally I prefer analogue controls and meters for PSUs, but when I'm measuring DC linearity it is convenient to be able to increment the voltage in 0.1V or 1V steps with digital inputs.
Consider getting three separate units or a dual plus a single; that will give you far more choice.
Consider getting cheap old PSUs; I seem to pick them up for £10-£20 at local auctions. They will probably work; if not you haven't lost much. Many may require the pots are cleaned with IPA or Craig Deoxit, some will require replacing some electrolytic capacitors. Both those things are much simpler/faster/cheaper than building you own PSU from scratch!