I reccomend consulting the Secor guide for overland hikes through the sierra https://www.amazon.com/High-Sierra-Peaks-Passes-Trails/dp/0898869714
You've got some good info it sounds like. The pinto side of glacier is indeed class 3, with parts of the pass quickly turning to class 4 if you go off route. It should be easier to traverse on such a dry year like this one, but try to get info on if there is any lingering ice on the pinto side before you go, you'll want an ice axe and appropriate footware if the route is still icy. The old trail from the meadow (groundhog meadow) is much more vertical and also can be hard to follow, but is shorter, if you're familiar with the route and in good shape it's a good option. The trail up to monarch lake is super well graded and easy to hike, but longer. Taking the route up towards sawtooth from there has you pass right by glacier pass, it's longer buy much easier and harder to get turned around. As soon as you head past monarch you're off trail. The route over glacier is also off trail. Don't go down a chute to go over the pass, you should find the stand up class three route if you hike all the way to the sawtooth side of the pass and look over. You might see old anchors in the bedrock from when there used to be a trail. If you walk up to a cliff turn around, try a different approach. When you get over the pass head towards spring lake. It's way downhill and it sucks when you're about to climb over blackrock but holding elevation does not work. Don't wander too far right and into the steep glaciated rock. If you hold left and straight you should be able to stay in class 3 walking all the way to the lake. To get to v Blackrock pass trail from there just traverse cross slope at elevation around. You should be able to see the trail plainly from several vantage points on your way to spring lake and spy a good route. Get beta from the front country rangers. Go your first time with a friend who is familiar with the route or be willing to turn around to find the better route. I reccomend this book on hikes in the southern sierra httpss://www.amazon.com/High-Sierra-Peaks-Passes-Trails/dp/0898869714
It should be mostly snow-free by July. I HIGHLY recommend the info on it from Secor in The High Sierra: Peaks, Passes, Trails.
Not sure what's going on with High Sierra Topix lately but there's at least a dozen people there whove been over it. Hopefully the site comes back soon.
Just curious, why go over Pants Pass and drop into Upper Kern (which is quite nice) when you could go over Pyra Queen Col and drop into Kaweah Basin, which anyone who's done both would agree is a much better time.
We did something similar last early September. Weather-wise it’s about the best. But of course that can vary by year. For tent sites, you’re not going to have a problem. It can get crowded at Benson, so if you’re itinerary allows it, arrive there earlier in the day. Dry stretches? Pay attention to hydrology on your map. But water is plentiful. Matterhorn is fun. Study the recommended routes ahead of time and take your time, especially if you haven’t done similar exposed high passes.
You might consider picking up Skurka’s Yosemite High Route Guide. Even if you don’t select from his route options, you’ll find good information there. You may also find some good information in Secor’s book, The High Sierra: Peaks, Passes, Trails. Finally, I recommend poking around over at High Sierra Topix, especially the pass database.
More peakbagging references than trail references (but most peaks are accessed by trails)
Since onion valley was brought up:
https://www.amazon.com/High-Sierra-Peaks-Passes-Trails/dp/0898869714