So here's what I went with:
+3 Hound of Griselbrand
+4 Golden Hind
-4 Ohran Viper
-4 Caller of the Claw
I don't have Temple of Abandon yet, or I do and I don't remember where it is (which is not good but I can solve that problem with a little research) but I've tweaked the mana base to add a little more red.
Hound of Griselbrand was an addition because I wanted a creature that had 3 power to dig further with Cream of the Crop, and the Undying ability meant I could get extra value out everything.
The initial changes yield positive results: I played against Matt as he threw a Pox deck and a War-Riders deck at it and I won pretty solidly both times. Avalanche Riders and Acidic Slime were critical in impeding Matt's plans, mostly targeting lands but also stepping in to destroy Haunted Plate Mail in the Pox match. However, I never got both Primitive Etching and Cream of the Crop out at the same time. Still, both cards appeared on the table during various games and the effect was always positive.
Matt's perspective on Razorclaw was interesting; he started off suggesting Dryad Arbor-a card I cut because it didn't combine with both Primitive Etchings and Cream of the Crop. For me, the Arbor was going to be a drawback more often than not, because Cream of the Crop will show up earlier in the game. Primitive Etchings is there to seal the engine up and draw more cards than my opponents.
Matt's other suggestion though? Simian Spirit Guide. His thinking is that I could even cut a couple lands for the Guide, in order to get more benefit from the Primitive Etchings, and later in the game, just cast the creature.
That's a hell of an interesting idea and I think I might try it.