This photo shows the clamp still in place and the bolts inserted about two to three turns. At this point, if you have subscribed to my installation method, you may begin tightening the machine screws in an alternating pattern. If you subscribe to the NFM method of creating a "gasket" follow their instructions.
It's very important, for the seal, and even distribution of sealant under the trim ring, using either method, to tighten the machine screws so the trim ring compresses as evenly as possible.
I find it much easier to tighten until you have some resistance, then stop and wait and repeat. I would move onto another project and come back fifteen minutes later and take another few turns. Doing this allowed the butyl to compress more slowly and evenly than force tightening all the screws immediately.
You'll notice the Tef-Gel around the bolt head which made for easy turning with minimal grabbing of the two surfaces. Once done, I simply wiped this excess up with paint thinner.