Overflow Question

[Laddy]

I'm currently plumbing a 55 with corner overflow. In the overflow area there are two holes drilled, one for the drain, and one for the return. I am going to use both as drains to the sump, however I have some questions regarding the first and second standpipes I have. The first standpipe I bought from Durso's site, 1 1/4" pvc for the 1' drain. The second one I am going to build myself. I'm wondering about the height of the second one, which is 3/4" pvc by the way. Should the drain line be below the main drain, or above. I'm basically looking for redundency with the two drains. Any help would be appreciated.

To recap: using the two drains in a standard 55g with corner overflow. One supports a 1 1/4" durso, the other will be made by me. Would like to know if there are any concerns in placement height of the smaller drain (3/4") which would effect water movement etc.?