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I completely agree with the guys that say you're slightly underpropping that engine... get the RPM mid 8000 ish. Anything more is just a wast of time.
The 18x6 is to small, I don't know the wide blade verion but on average a "w" is worth an inch so you're looking at a 18x7 which again, looking at your RPM figures is a little to small A 16x10-18x8 would be better.There are a group of guys out there that believe this engine should be reving like a small 2 stroke. As I said, they're out there , way out there. Don't listen to them.

Next, you need at least 1 extra head shim with that engine, some use two, have you got that? Get it.
Next, F type plug perod. Your fuel is OK.
The muffler is crap but there isn't anything you can do about that.
The one way valve that comes with a Cline isn't the best, when you get the chance change it for a YS one.
A presurized tank really takes some action, most off the shelf hobby tanks just can't take it. One day again when you get a chance change it for a Tettra/MK or at least a Kavan with the metal ring around the neck. That way you want be looking for a radio compartment soaked in a pint of glow fuel because the crappy tank split.

Remember also that you need to completely run in the engine (and I mean completely) before you should connect the cline or a pump for that matter. Unless you do this you'll end up looking like the other Turkey's here that are chasing an engine set-up, or is it a pump set up, or may be it's the engine, no it's the
pump... you get the picture. Run the engine in, set it up so it performs perfectly, than add the cline into the equation and notice what changes it's made and adjust accordingly.

And lastly, make sure that when to check for idle to full throttle transition, you roll the throttle stick from bottom to top... a "one and two" count. Thats the professional way.The Sunday hack just bangs open the stick like a total plonker. They even use the throttle that way when flying. Don't do that, it's a throttle, it's not an on/off switch. Apart from making them look like a complete amature, it's serves absolutely no real purpose and tells you nothing about the engine.
Every engines will occassionally cough and ****ter... that's the nature... what di we learn from that? When we roll the throttle we can hear what's happening from idle all the way to fully open. That way we can hear the rich or lean spots through out the transition and again adjust accordingly.

By the way, all the guy's I know operating that engine on the pattern circuit are using the simple, humble Perry.
If it ain't working with the Cline which it may well not, you know what to get.