Yael-
I think you need to avoid clinch range altogether. THIS is the answer:
http://www.yellowbamboo.info/home%20page.htm
Seriously however...what type of tie-up are you tinkering with? If you have say a head&arm or single underhook you are normally looking for some kind of hip toss or leg trip. Occasionally one will go for an ankle pick from clinch, this is certainly done in free style wrestling.
I'd focus on attaining these positions:
1-single or double underhooks.
2-Side position with opponents near side arm trapped.
3-Thai clinch. Hands on occiput, elbows on clavicles.
We will be looking at all of these in future PM issues. If you can get some video of what you are doing we can offer some input on how to tinker things.