Effects of SBIG API autoguide lag, and image download


I am interested in using SG Pro in setting up remotely with an old SBIG 10XME, which previously I ran with CCDAP. I have read here about the lag introduced to guiding by using API - <= 0.6secs quoted here, and elsewhere i have seen >1 sec quoted. Could I ask what has been experienced in the field. Does this have a significant effect on guiding performance?

Also I have seen a comment suggesting instead the use of an external guide, to avoid the loss of guiding during image downloads in these SBIG cameras with the guide sensor behind the filter wheel. This previously worked OK for me in CCDAP, with perhaps approx 30secs after each download required for stable autoguiding to be reacquired. What is the reason for recommending the switch?

If both of these are major issues, then I would need to consider either different guider, or different software, but keen to avoid if i can