diff --git a/.github/workflows/ci_integration.yml b/.github/workflows/ci_integration.yml
index 38cab2b6..d656606c 100644
--- a/.github/workflows/ci_integration.yml
+++ b/.github/workflows/ci_integration.yml
@@ -9,7 +9,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: codebuild-CryptoToolsCI-linux-aws-dynamodb-encryption-python-${{ github.run_id }}-${{ github.run_attempt }}
     strategy:
       fail-fast: false
       matrix:
@@ -65,7 +65,7 @@ jobs:
         run: tox
 
   coverage:
-    runs-on: ubuntu-latest
+    runs-on: codebuild-CryptoToolsCI-linux-aws-dynamodb-encryption-python-${{ github.run_id }}-${{ github.run_attempt }}
     steps:
       - uses: actions/checkout@v4
       
diff --git a/.github/workflows/ci_static-analysis.yaml b/.github/workflows/ci_static-analysis.yaml
index 1dd67a65..6d0b428e 100644
--- a/.github/workflows/ci_static-analysis.yaml
+++ b/.github/workflows/ci_static-analysis.yaml
@@ -12,7 +12,7 @@ permissions:
 
 jobs:
   analysis:
-    runs-on: ubuntu-latest
+    runs-on: codebuild-CryptoToolsCI-linux-aws-dynamodb-encryption-python-${{ github.run_id }}-${{ github.run_attempt }}
     strategy:
       fail-fast: false
       matrix:
diff --git a/.github/workflows/ci_tests.yaml b/.github/workflows/ci_tests.yaml
index 06e8ce5e..2e31bbf4 100644
--- a/.github/workflows/ci_tests.yaml
+++ b/.github/workflows/ci_tests.yaml
@@ -12,7 +12,7 @@ permissions:
 
 jobs:
   tests:
-    runs-on: ${{ matrix.platform.os }}
+    runs-on: ${{ matrix.platform.os == 'ubuntu-latest' && format('codebuild-CryptoToolsCI-linux-aws-dynamodb-encryption-python-{0}-{1}', github.run_id, github.run_attempt) || matrix.platform.os }}
     strategy:
       fail-fast: true
       matrix:
@@ -21,9 +21,6 @@ jobs:
             architecture: x64
           - os: windows-latest
             architecture: x64
-          # x86 builds are only meaningful for Windows
-          - os: windows-latest
-            architecture: x86
           - os: macos-latest
             architecture: x64
         python:
@@ -63,10 +60,12 @@ jobs:
       - name: run test
         env:
           TOXENV: ${{ matrix.category }}
+          # tox reads pip's output as UTF-8; Windows writes it in the console code page otherwise.
+          PYTHONUTF8: "1"
         run: tox -- -vv
 
   upstream-py311:
-    runs-on: ubuntu-latest
+    runs-on: codebuild-CryptoToolsCI-linux-aws-dynamodb-encryption-python-${{ github.run_id }}-${{ github.run_attempt }}
     strategy:
       fail-fast: true
       matrix:
@@ -85,4 +84,6 @@ jobs:
       - name: run test
         env:
           TOXENV: ${{ matrix.category }}
+          # tox reads pip's output as UTF-8; Windows writes it in the console code page otherwise.
+          PYTHONUTF8: "1"
         run: tox -- -vv
diff --git a/.github/workflows/pull.yml b/.github/workflows/pull.yml
index f13598b9..1c00217e 100644
--- a/.github/workflows/pull.yml
+++ b/.github/workflows/pull.yml
@@ -23,7 +23,7 @@ jobs:
       - call-integration-tests
       - call-static-analysis
       - call-tests
-    runs-on: ubuntu-22.04
+    runs-on: codebuild-CryptoToolsCI-linux-aws-dynamodb-encryption-python-${{ github.run_id }}-${{ github.run_attempt }}
     steps:
       - name: Verify all required jobs passed
         uses: re-actors/alls-green@release/v1