Blending to reduce IBU/SG recipe question

[StenbergBrewing]

Not sure what to do. I have a batch of Sticke ALT I accidentally made 100 IBU instead of 50. I then proceeded to boil down and go "imperial". However I changed my mind and want to brew it again without bittering hops and blend. The first batch ended up 5 gal with OG 1.063. I want the overall blended beer closer to my original recipe of 1.056. So the new unbittered 5 gal batch will have to be weaker in SG (1.049 5gal) as well. However my question is this...

Should I reduce ALL fermentables equally and keep the same % of ingredients? Or just reduce the "base" malts of pils and Munich?

And note, my efficiency is 90% so I already changed my original recipe from research I did by reducing the pils and Munich by 1/2 lb each to hit the SG I wanted but left the other grains the same. Not sure if this is the proper protocol either but it's what I did...

Recipe in photoView attachment ImageUploadedByHome Brew1446919655.627769.jpg

 

[StenbergBrewing]

Better yet, I've wanted to brew a Düsseldorf alt and Sticke alt anyways. Maybe I could brew and split appropriately to end up with both. Volumes may differ but if one could be higher OG and other weaker as well as the IBUs respectively, that would be great. I could then dry hop the Sticke and leave the Düsseldorf. Then I could have two different beers instead of 10 gal of the same. This is getting confusing