Assisting students with large programming assignments takes too long in class
The problem, in my view, is a misplaced assumption that students should never see one another's code and that seeing it would somehow or other "pollute" the student's mind in some way or make grading invalid. 

A clear solution, provided that you can give up that assumption, is to have the students work in pairs in the tutorial, giving help and advice to one another. A more radical approach, that I also favor, is to have students work together to develop the code in the first place. 

It has been observed (I have seen the video) that when students work together they seldom need outside help and call for tutor help only rarely. When students work alone and wait for the tutor they are mostly idle while waiting. 

The reason for this is that, while both students in a pair may have problems, they seldom have the same problems and so can support one another's learning. When a tutor's help is needed, there has already been a deeper analysis of the issue at hand, since there were two minds working on it. 

If you worry less about grading, and less about some students "slacking" you can do a better job overall, especially for those who are interested in learning. Students can learn from one another. It isn't essential that they learn  only from the instructor. 



My experience, also, is that when a "better" student helps another, both benefit from the experience. The helper gains deeper insight by having to verbalize an understanding that may be only partly formed. 

When abrasive personalities get in the way of pairing, the one that is abrasive needs to learn better behavior in any case if he/she is to be successful in the long run. Instructors need to watch for this, of course, and offer advice as needed.