I used to gig with them quite a bit, but there is an inherent flaw in their design. The higher the tension, the greater the issue of slippage. The post itself will be incrementally pulled out of contact with the tuning gear with the greater the tension. So if you use a beefy set of flats - most people did back then - tuning will be a serious issue. Any attempt at using long scale strings cut down will definitely be a nightmare. If you take one apart - and I took several apart - you can physically create the issue to see how it happens. A good fresh set of Roto short scales and you will not have much of a problem. GHS, or such stuff, and you can tune it and have the string go slack in a second.