OK that does modify my critique, but it doesn't change the end result. the second grip did in fact put some in a more or less in line but not a close line, and you had what would be counted as fliers with one round almost through one of the flier in the center, Ok that made no sense. 4 fliers with 2 of the 4 very nearly in the same hole. and of those 4, 3 were in the green with the fourth way high right of middle top but still in the target. If you really wanted to analyse that group it appears that you had pretty good control of your weapon but did something to change that control at about the 5th and 6th round. So possibly the ammunition is part of but not necessarily the culprit.
The first set in the lower left is literally all over the target with at least 1 flier out of the target completely and one as near as I can see not even on the paper. However you were holding the pistol for those shots I would say, and it's a guess, that you limp wristed the set. Considering, all the other targets showing I would say you shoot very well and once you find your center you will be drilling 4 inch or better groups. I would guess that you may even have used your off hand for those. Or you went with your less dominate eye, or both. The only other explanation is that your left hand over powered your right during that sequence. Meaning you pulled your weapon instead of supporting it and pulling down to control rise.
The one target that is throwing off my guess is the first one and that's just so unlike the others I would like to know what stance and control you used for that target. As for the target with your brothers reloads all I can say there is that it proves my point about your ability to shoot and also he is a damn good re-loader. Which also goes to prove my point about the factory ammunition being part and parcel of your other three targets no matter how you held the weapon or the stance you used. Granted it was 5 yards closer but if you look at your other 10 yard target the rounds impacted over a much, much great area. Even counting the fact you fired 18 rounds instead of the 10 you had been using. No matter how I count the holes not one pattern seems to be even close to the pattern (or grouping if you perfer) of your brothers ammunition. It would have been very intresting to see what the different speeds the rounds were traveling at since the speed of the round affects the trajectory of the round.
If you aren't allready offending at my critique and I was not trying to offend you in any way, I would suggest that you took those same rounds to the range and re-shoot the sequence, but only use one stance and grip for all the shots. About the only way you will figure out what works best for you out of your weapon. Personally if I was you I would work out a deal with him to buy all your ammo from him and use that and what even stance you used to shoot them with this time.
Seriously the difference between that target and the other 3 is extreme, day and night difference. Heck I would buy ammo from your brother if it worked in my primary carry weapon and the one I will use for competition. The first being a fully tricked out CZ 75 Pre-B and the second one(s) CZCustom CZ 75 SP-01 Custom Shadow, as well as it did with your 85. That is if I can afford to buy from him.
If you use that stance and grip and his ammo, the only thing you would need to work on would be your sight picture and where you you have to aim for the distance, and once you had that down you would be in the top 10 if not higher depending on what competition you were in or wanted to try if any.
I hope I didn't offend you (much) and everything (almost everything) I said was a guess, but there is no denying the fact that what ever stance and grip you used coupled with your brother's ammo is the one you should go with. At least IMHO anyway. Won't really know I suppose unless you take my suggestion and re-shoot the test using only the same one stance and grip on all 4 types of ammo and distances.