Brendan,
I have a Black Diamond 7" Mak. I'd suggest instead you ditch the laser tomfoolery and do it the old tried-&-proven way used for the previous 50 years. You need:
a) a "cheshire" eyepiece (old one with a small opening and no lenses, eg an old 4mm ortho minus the lenses);
b) medium power eyepiece, say 25mm;
c) higher power eyepiece, about 13mm; and
d) a steady mount, preferably one that tracks (doesn't have to be well aligned).
1. Start in daylight with the scope pointing at the sky and insert the cheshire eyepiece. Looking through this, concentrate on what you see in the secondary mirror, which will be a reflection of the primary. If the corrector is aligned properly the perimeter of the primary should be visibly concentric with the perimeter of the secondary. If not, adjust the tilt of the corrector till it is. To work out where to make the adjustment, hold a finger in front of the scope and move it to where the gap between secondary and primary appears greatest. Find the adjustment for the corrector nearest this point.
Repeat until the reflection of the primary appears concentric in the secondary.
http://www.robincasady.com/Astro/myimages/collim.html
2. Now the primary, do this on a clear night . Insert medium power eyepiece and find a bright star, centre on this and look at the out-of-focus rings. When properly aligned, the rings will be concentric. If not concentric, hold up a finger in front of the scope and you will see this in the out-of-focus rings. Move your finger to the point where the rings are most mis-aligned, and use the corresponding screw to align the primary.
Repeat until the rings are concentric.
3. Swap to higher power eyepiece and repeat 2.
Note: A 7" is big enough to suffer internal tube currents and you may have to wait till these die down. Another solution is to stir up the air inside by swinging the scope around a bit, I find this helps a lot.
All told it can be done in 30 minutes or so at dusk.