OK i understand how the west CW up slew checkbox works now. when an offset is given, CW up slews will not occur between the limit and the offset - a flip will occur. CW up slews will only occur between the true meridian and the offset. the checkbox says “within west limits” which meant to me that CW up slews are possible between the meridian and the limit. this is why i never had it ticked, because i thought it would prevent a flip until the limit was reached. i thought the offset value was only used to compute the meridian delay sent to SGP.
all i ever needed was a way for SGP to finish any image in progress when it crossed the true meridian, then immediately flip. what you have implemented is more flexible than that and is a superset of what i need. possibly “limit to meridian” would give me what i was looking for but it is not clear why APCC did not flip the mount when it was ticked - see below; i think it was probably sending a delay of 1 minute to SGP this whole time (which should have been OK)
by playing around with this, i can see that if “west CW up slews” is not ticked, APCC is unconditionally sending a meridian delay of 1 minute to SGP. in addition i can see that if “west CW up slews” is ticked, but “limit to meridian” is also ticked, APCC also sends 1 minute instead of the computed value from the limit/offset which seems correct. while this seems safe, it must be occasionally causing SGP to issue a slew before the meridian is reached, although you’d think the opposite would be true - the mount would be a minute past its own flip point at the time SGP thinks it is eligible to flip. regardless i had many nights where the mount did not flip in this configuration.
also one minor thing - when everything is configured properly APCC automatically sets a meridian delay, which makes sense. however, if i untick the “CW up slews” box, the meridian delay persists in APCC. since it was set automatically, maybe it should be restored automatically? or at least warn the user that a meridian delay is still set?