I think the hide looks fine. Its ideal to have the same hide on the cool and warm side. Thatway the snake just chooses the side that has the ideal temp. I highly reccomend getting a good quality thermostat (herpstat) with a good heat pad (or flexwatt if you prefer). This way you can set up the warmside and have a nice constant temp. For the cool side, if your house isnt warm enough you could use a light but this may not be ideal if humidity is an issue. A humid hide can be useful especially during the shed cycle. It is ideal if you can have humidity around 60 all the time though. This reduces the chance of respiratory infection.
I think your tank looks really good, but I cant stress enough the importance of proper heating. Please do not skimp of temperature monitoring, it really does matter. If you want to use a rheostat that is fine, but you just need to monitor closely with a good quality probe thermometer. You seem like you really care to get things set up right and that great. One last ball note: the really tall stick, I would remove. Balls are kind of clumsy climbers and can fall from stuff like that. Its better to keep balls on the ground
Oh, if you want to get a corn that is fine too, but please don,t house multiples in the same tank. Its not healthy for them. Some people do it but a responsible corn owners steer away from such nonsense.