Hop solution after fermentation start?

I participated in a group brew with the following recipe:

20 Gallons of wort, 10 gallon boil

33.00 lbs. Briess LME- Gold
3.00 lbs. Crystal 40L
0.50 lbs. Special B Malt

3 oz of Warrior Hops 60 min
2 oz of Warrior Hops 45 min
3 oz of Cascades Hops @ flameout

Everyone used a different yeast strain. I used S-05 (was great the last time we did this same recipe).

I dry hopped 1 oz Cascade and 1 oz Centennial in the secondary last time. It was really good, but I wanted more flavor.

This time, I'm interested in getting big Cascade flavor into my beer. After reading up on the subject it seems late addition is the way to go. Unfortunately this was a group brew so anything I did to the basic recipe would change the other brews too so I didn't do anything. I have my wort fermentating today (brewed yesterday 8/23). I was thinking...
What if I boiled up 1 gallon of water with 1#DME for 15 mintues, tossed in 2.5 oz of Cascades at flameout, chilled to 60s (my fermenting temperature), then tossed that in on top of the now fermenting wort?

Whatcha think?

TIA!

If you want more hop flavor, use a 15-20 minute boil.

So bring water to a boil, toss in hops and DME, boil for 15 then chill?

This is what I did.

Brought 1 gallon water to a boil.
Tossed in 1# DME and IC, brought back to a boil after stirring DME in.
Tossed 2.5oz Cascades in when boil came back.
Boiled for 15 minutes.
Turned on IC chilled to below 70F.
Poured wort into sanitized LME jerry can.
Brought wort to fermenting vessel and poured on top of the fermenting wort.

My fingers are crossed that I didn't mess anything up. The wort was the greenest I've ever seen and it was very grainy from all those hops in a small volume. I hope my splashing down the hops from the IC and kettle sides won't give me HSA issues. Wort smelled awesome!

I'd like to know how it turns out. I've never tried it so I'm curious.

Bottled my Vulcan Warrior today. It smelled awesome and tasted great too. I've got the hydrometer sample in the fridge cooling down for a better taste later. 3 weeks and I'll let you know how it came out. Very clear, so I am pleased with that.

3 Weeks are up and the beer came out just fine. I didn't get as much hop flavor as I had hopes, but it sure has plenty of aroma and it definitely did bump up the citrus taste some. I think I should have bumped up the OG of my mix because the extra volume detracted from mouthfeel and the bitterness. I know this based on the last time we brewed this and what it came out like. Not something I'd do on purpose, but in a situation like this, I think I've proven it will work.