I don't know how much social welfare spending could be considered "Too much" - whether you measure it by society in relative or absolute terms.
However there are usually a few indicators that tell you when your social welfare spending has become problematic.
In other words, you know state welfare spending has become problematic when;
1. People from other countries [or sometimes other states in the case of the US which has federal and state welfare] are going to your country not for employment but for welfare benefits
2. A permanent underclass has been created that represents a significant bloc of subsidized voting-power.
3. State middlemen and social workers are so numerous as to become a secondary boc of subsidized voting-power. The benefits to the taxpayer [and in some case, the abstract benefits to the working poor] are diffused compared to the concentrated losses born by these people if programs were to ever be scaled back [or even had their growth slowed]
4. People don't look for employment because of unemployment benefits.
Basically, you know when you're spending too much on welfare when you've created a political situation where cutting welfare benefits is politically impossible.
Some people claim that job training and the 'give a man a fish' philosophy is better for Government welfare. I could not disagree more. Straight-up welfare at least avoids the problem of creating a managerial class that exists to the extent that the poor are dysfunctional. Job training programs have existed, at least in the United States, with questionable success.