OP is having his table recovered and leveled. There would be no excuse for a bad cloth stretch.Table could be level but still roll off due to a bad cloth stretch.
I had a similar experience. To flush the slates they simply pushed them together, superglued the outside 4"then beeswaxed the hell out of it. The slates were not flush. If you slow rolled a CB when it got to the edge of the wax it would roll off 2-3". Upon scraping up the wax I found one side was tissue thin, the other probably 1/16" of wax. I went through the process of flushing the slates with a bottle jack, completely redoing the seams with bondo (boiled linseed and wiping takes the wax off). RKC helped me get it level over the phone and I put new cloth on the bed. Glen was super generous with his time and knowledge, it now plays as good as any table I've played on. Buying new cloth to replace 5-6 month old cloth was a bitter pill to swallow but now it's a great table. Luckily my nephew needed new cloth for his valley and since their slate is smaller I can re-use the practically new cloth and it helps him out.I got hosed also by a Diamond dealer. The cloth stretch was all crooked, and a month later after buying my own Starrett level, I found the level off up to 3 lines in spots. I now have the level pretty much within 1 line but up to two lines in spots. That's the best I can get without risking breaking the seams for now. I will straighten it out when I recover, but it is pretty good for now.
Live and learn with unknown installers, I've learned to never trust them, always double check as when they are 4 hrs away, good luck getting them back.
I would never be passive with an installer again, if you don't have your own level, ask to use theirs when they ask you if it's ok. If they are using a carpenter's level and they ask if you think their leveling job is ok, tell them you wouldn't know with the level they are using.
A Diamond table with a single piece slate can be easily corrected for level, a three piece gets much more difficult depending on how far off, and where it is out of level.
Here's the million dollar question. If you're having the cloth replaced on your table, I'm going to go out on a limb and assume you've got a few thousand hours put in playing on it.I’m having my table recovered this week & they’re going to ask me if I’m happy that the table is level. What is the best way to quickly check that it is level?
Thanks.