Let's get people thinking a bit about what drop brackets actually do.
If you go to smaller drivers you may do this to get your approach angle corrected again.
OK, create an imaginary center to your sled. Maybe the drive shaft. Now think of your sled as a teeter totter. Now think what raising the back of your sled will do............................think about it.......................keep thinking.

think some more...........Figure it out or give up. Lol It is creating more ski pressure. This may or may not be welcome. Might create a very "heavy" steering feel.
Now keep in mind the rear suspension is very adjustable even back then. So you can adjust ski pressure and transfer to some extent already.
Example. My sled I want to tip over very easy in the deep snow. So, I will be removing the sway bar. (hope it works Lol) This will leave me with a sled that really handles like crap on the trail. So for my situation i will welcome some extra ski pressure. And in the deep snow I will welcome an improved approach angle to the track.
i would. should actually do all three, third being the upper crosshaft supporting the track. on a 2" drop, i would drop the front scissor about 5/8" same on the center. by doing this it will help retain balance and geometry and not load the skis as much making future adjustments easier.
Just wanted to touch on this. Depending on how much you drop the rear and why you did it. Are you changing drivers, do you need more clearance? If you drop the rear you certainly should adjust the cross shaft to stay in line with what you are doing in the back. Keep in mind most newer sleds don't have this even with 163" tracks. (just saying) Lol I would only lower the front unless what you did in the back is netting some unappealing results. Too much pressure or track rubbing as described.
Another thing to consider is bolt spacing of your rear suspension mounting. Center to center. If you just bring brackets down, your bolt hole in the rear should actually be forward of the old position. Your rear suspension is actually pivoting downwards at an angle. Not straight. Hope that makes sense.