Hey,
The aux. lights must not be higher than the centre line of the vehicles head lamps.
The aux. lamps if used for fog lighting applications, will be installed connected to the vehicles Low beam(dipped) circuit and aimed properly.
If the lights are used for driving lights, then the lamps must be connected to the high beam (main beam) circuit.
You are only allowed to have a total of four sets/pairs of lights operational on the front of your vehicle.(This includes head lamps, turn signal/front marker lights, and up to two pairs of additional lights {this includes factory fog/driving lights})
As far as lights mounted on the roof:
You may have as many as you like. But, they are not allowed to be functional while the vehicle is operated on a highway or other wise public road. The bulbs must be removed or the wire connection must be disconnected while on a public road so that the lamps cannot be switched on while driving.
So as far as the Dick Cepek lights go... Ya mount them. Just be extra careful with them, and if you use the lamp covers, most of the time the local constabulary leave you alone if you're good.
I've got 4 Bosch Rallye lights(each lamp* 10inch diameter and 130 watts, thats 520 watts!) on the front of my '76 Mini rallye car, and was out one night on a stretch of straight highway, I had just adjusted them for long distance projection and I'm flying up the road... On the horizon, on the side of the road I see white fender with reflective stripes, then white door with R.C.M.P. shield(reflective as well), then white rear door/quarter panel !
To make a long story short, $198.00 fine for excessive light! (censored) @ss hole!

Mind you, I could see the colours of the R.C.M.P. shield from far far away!
(contact your local R.C.M.P. and ask for rules and regulations regarding auxiliary automotive lights)
What I quoted here is correct to the best of my memory. The information was given to me by am brother-in-law a retired R.C.M.P. Constable of 20 years who's done it all.
Cheers
Ry'
BTW, I have 4 6'X9' Dick Cepek 130watt lights...
They are going on the roof with a custom made lamp bar which brings them closer to the edge of the windshield for better aiming.
I also converted them from H3 to H4 double filament bulbs.
http://aa.bosch.de/aa/en/static/produkte/lichttechnik/zusatzscheinwerfer/rallye.htm These are the lights on my Mini