Gretsch Deltolux Parlor Replacement Tuning Machines

[nrand]

I picked one of these guitars today
Out of the box the action was not bad, and once I raised the sound hole pickup with a couple of small rubber bushings the sound is quite OK
However, the tuners leave much to be desired as they go out of tune constantly and cannot be adjusted to fix the problem.
Is anyone familiar with these who can recommend a set of 3 a side replcements?
TIA