My suggestion for gripping is always be aggressive. People should feel beat up after a good grip fighting session. To me gripping is like climbing a tree. Get one grip...anywhere you can...and slowly work towards the grip you want. If you grip him, he will grip you...then you work to the grip you like...grip by grib. But, throws, like all things in grappling are opportunistic. If you can't really get that grip on someone, or someone is simply refusing to grip with you, you have to go with what is there...and this throw might not be there for you...at least not with this particular grip.
I like the tree similie. Makes a lot of sense. Thanks!