I’m a QS and unless I was doing any of the work myself, I would not be providing any materials. Let your subcontractors take the risk on late deliveries, waiting time, errors, quantities etc. Unless you really, really know what you’re doing – let the subcontractor supply. They’ll get better rates than you, too.
You need to give us more info, but a better approach would be to write a scope of works for each trade, clearly defining exactly what it is you want them to do, and get them to price on a lump sum basis. An important thing to consider is the interface between each trade – identify who is doing which bit.
The three “tenets” of quantity surveying are time, cost and quality – be clear on what you want, when you want it, and how much you are paying for it.