3zub, the rollout shelf will be a compromised solution, no matter how sturdy the retracting hardware. The best platform for a turntable always will be the most stable and rigid solution you can come up with. If there is any way you could live with either 1) a fixed position shelf above your amplifiers (sticking out into the room and not retractable), or 2) a small separate floor standing platform, you would be MUCH better off.
Alternatively, can you live with your amps being on the floor behind or beside your speakers? If so, you might find a way to re-configure your other gear to allow some space inside one of your niches for a turntable (preferably the upper niche for ease of access).
If you must go the roll-out shelf route, get the most well-engineered, tight-tolerance and over-engineered hardware you can source.
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Alternatively, can you live with your amps being on the floor behind or beside your speakers? If so, you might find a way to re-configure your other gear to allow some space inside one of your niches for a turntable (preferably the upper niche for ease of access).
If you must go the roll-out shelf route, get the most well-engineered, tight-tolerance and over-engineered hardware you can source.
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