My apologies, cg_* variables aren't in the file I'm thinking of. Here is a section of the diff from my build queue slowdown mod (src/game/g_main.c). Playing around with this should give you most of what you want.
Index: src/game/g_main.c
===================================================================
--- src/game/g_main.c (revision 2048)
+++ src/game/g_main.c (working copy)
@@ -74,6 +74,8 @@
vmCvar_t g_minNameChangePeriod;
vmCvar_t g_maxNameChanges;
+vmCvar_t g_buildQueueSlowdown;
+
vmCvar_t g_alienBuildPoints;
vmCvar_t g_alienBuildQueueTime;
vmCvar_t g_humanBuildPoints;
@@ -196,6 +198,8 @@
{ &pmove_fixed, "pmove_fixed", "0", CVAR_SYSTEMINFO, 0, qfalse},
{ &pmove_msec, "pmove_msec", "8", CVAR_SYSTEMINFO, 0, qfalse},
+ { &g_buildQueueSlowdown, "g_buildQueueSlowdown", DEFAULT_BUILD_QUEUE_SLOWDOWN, 0, 0, qfalse },
+
{ &g_alienBuildPoints, "g_alienBuildPoints", DEFAULT_ALIEN_BUILDPOINTS, 0, 0, qfalse },
{ &g_alienBuildQueueTime, "g_alienBuildQueueTime", DEFAULT_ALIEN_QUEUE_TIME, CVAR_ARCHIVE, 0, qfalse },
{ &g_humanBuildPoints, "g_humanBuildPoints", DEFAULT_HUMAN_BUILDPOINTS, 0, 0, qfalse },