The Balance between "% Circling" and "MacCready Speed to Fly"

I have been told over the years two consistent things: when trying to
achieve the fastest possible cross country speeds, 1. Try to minimize
circling as much as possible and 2. Fly the true maccready airspeeds
between thermals.


But these two things contradict. The first couple days I flew at
Perry this year, I flew true maccready airspeeds between thermals.
The lift was strong, 5-7 kt thermals to 6-7,000 feet. So I flew about
70-80 between thermals. My average speed was then in the upper 40's.
Then for the later part of the contest, in the same weather
conditions, I delibertly did everything I could to reduce my %
circling. I flew 50-70 kts between thermals and drastically reduced
my circling. I had one flight with 15% circling and my resulting
average speed was 52 mph. So by slowing down I had a faster speed.

I understand that thermal density plays a big part in deciding what
speed to cruise at. If the thermal density is lower, it may be best
to stretch out the inter thermal glides to stay in the altitude power
band. I fly faster when the lift sources are obvious, gaggle, clouds,
birds, smoke. But when the lift is invisible, I slow it down to
stretch out my glide. I also slow waaay down if there's no good
landable fields insight....for safety.

So is there a balance between % circling and true maccready speed to
fly? What are some things that can flex your true maccready speeds up
or down?