Is the card you mentioned placed before the first mirror? What sort of pattern do you get after the 2nd mirror before entering the head?
If so - the dimension is about right as the lens focuses the beam but the double beam doesn't sound right - check be the output coupler lens on the tube, it may be damaged or the tube could be on it's way out.
Using two LS3060's and an ex 3020 user
Please note I am not employed by HPC, any advice or recomendations I give are based on my own experience and are not necessarily the same as HPC's. First point of contact on any hardware issues should be with HPC