I never found tube glue to be as effective as most thin bottle glues are more efficient at welding the plastic together. If you use a small paint brush or touch and flow applicator you can accurately get the liquid to flow along a joint by caphillery action. You do have to be careful with overflow and finger prints.
I always found that most tube glues often have airpockets that would flood at inopportune moments causing real problems with melting.
I do sometimes us Revell contacta where the glue is fed via a steel tube but find that blockages are a problem.
Liquid glue take a little practice to use like all materials and I have found that you get superior joins and use less glue.
This is my opinion based on my own experience over many years and hope it helps you.
Regards,
John