There is a lot of flexibility with slider sizes. Apex BASE uses the same slider size for:
200 and below (17 x 24) 210 - 250 (20 x 24) 260+ (23 x 28)
So in the middle case you've got two canopies with a 40 sq. ft. difference using the same slider. I've also personally used a 20 x 24 on a 260 with no noticeable difference.
In an even more extreme example, we recently built a 360 sq. ft. canopy that is using a 23 x 28...so that's a 100 sq. ft. difference on the same slider.
In your case, the size difference is very minor. I would expect that there would be no meaningful performance differences. And even if there was a meaningful difference on opening...doesn't the fact that you're after a sail slider indicate that this is for a skydive? Sail sliders are not intended to be BASE jumped. At least not the ones we build.
I know we chatted about this in e-mail as well, but wanted to share this for anyone else in the forum. =)
Sorry if this is a bit off-topic (if it's too much ,I'll do a separate post).
I've been testing some sliders recently and came up with a conclusion, which would be nice if somebody could check.
I found out that the size size of the slider (the span wise, i.e. how wide it is ) affects the speed how the canopy opens at the very beginning (e.g. if it slams or starts opening very slowly).
The second thing I found out is that the material doesn't affect the first phase at all but only the second phase i.e. the sniveling when the slider comes down. As an example I used an Atair slow slider, small mesh and big mesh and they all had the same "pull" at the beginning and the only difference was the time of the snivel.
I haven't tested how the chord wise size affects the opening - would be nice to hear something about this.
Found a 26''x28'' and played with in on several skydives. Spanked half way down and then pumped to get slider to come down (nose rolled tight). third skydive left nose open and the slider had a nice consistent speed coming down. Going to Switch to the 23x28 sail from Apex and give it a go nose open and nose rolled. The Fine Mesh 20x28 was knocking me silly, hurting my back and neck. Thanks for the Input and Insight.
For testing, you may want to do several jumps on the same configuration as on only one jump it may still be kind of random. E.g. on all kind of sliders I've had opening from slamming hard to scary slow and snively.
23x28 sail slider from Apex opening just right for me (2 jumps). Not too hard, not to soft. It's a smidge larger than stock, but not as big as the red sail slider I tried on many jumps that sniveled 26x28. Stock Mesh was 20x28.
Will do a few more jumps to make sure it's consistent.
My understanding of the situation is that a smaller "mesh" slider (large or small mesh) should slow the openings due to it restricting the initial canopy expansion that drives the slider down. While the opposite is true for sail sliders as the larger the slider is the more "sail" is available to slow the sliders rate of descent. (Obviously there would be preferred ranges for optimal openings).