Vertical on sandbed vs. horizontal on rock? (Maxima)

[becact]

Which position do you think would be best for a small maxima (~2 in)? On the sandbed,mantle facing up, in the middle of the tank, directly under the bulb and attached to a piece of flat rock under the sandbed, or perched on the rocks in about the middle of the tank, but angled so that the mantle of the clam is facing nearly horizontal (perhaps 30 degrees from horizontal)?

My tank is a Biocube 14, under a 14000k Sunpod metal halide. I will be adding supplemental LED lighting in a month or so.

I really don't have many spots on the rock to work with except for one nice one in which the clam would have to be angled like that.

 

[Miles.P]

Higher the better, especially for a small Maxima; they're very demanding for light

 

[becact]

thanks. I was able to position him about half way up, but pointing mostly upwards. He is probably about 30* from vertical, now. His foot already attached after about an hour after placing him there, so I guess he likes it, for now!