Replicating fixtures and renumbering them

Hi guys
i wonder how you deal with that....
lets say i got 6x Mac 2k with numbers 1 thru 6 and 10 Mac 600 Wash with numbers 101 thru 110.
No when i replicate the 6 Mac 2k and Change the fixture to be Alpha Spots then the numbers are 7 thru 12 showing copy from 1 ... and so on.
I want the Alpha Spots to be number 1 thru 6. Therefor i need to renumber the Mac 2k.... lets say to 1001 thru 1006.
The Alpha Spots are still showing copy from 1 ... and so on instead of copy from 1001....

I imagine you got a bunch of replicating to do.
How you renumber fixtures and stuff to not get crazy from what you replicated?
I find it quiet confusing with just replicating 3 types of lamps.