BOQ & Resource productivity

hi there everyone i am so honored to share information with you guys...

i have project with the following given information::

1. project BOQs
2. Resources productivity.

my approach at least "theoretically" with this project was as following:

1. getting the "Project Cost" from BOQ
2. and getting "Activities Duration" based on productivity of the resources assigned .

so i rolled up my sleeves ..and opened up Primavera p6 and did the following:

1. Duration type =fixed units.. to go with the fixed BOQ that i have "although i feel like even fixed units/time works as well" ..but whatever ...
2. i defined the BOQ as material resources.
3. and i defined resources (labor &non labor) units/time as per productivity requirements not calendar requirements which is 8h/d

        for example:

            for my steel fixer team i assigned thier units/time=225h/d

            as if 225kg/d

Now my questions:

1. is this a good practice.
2. how does that affect my resource usage profile in terms of overallocation units.

your prompt response will be very highly appreciated

best regards