The result of the beamdivergence after stacking depend on the lenses that are being used. Hobbybob was very satisfied with the lenses of laser4u.
Here,s the link:
http://cgi.ebay.com/Laser-Module-Hou...ht_1486wt_1137
We didn,t do a test, we just had some fun with trying a few lenses. The setup is capable of stacking 4 diodes and being staying toghether for a long time. The collimators are adjustable and so stacking horizontally is easy.
This is the last one that i have. I can get one more because the metalshop usually makes 1 more. They still have it.
I will help the people who bought a setup where i can. I can help you with getting the best lens for the setup. shoot me a PM if you want it.