connecting liners...any final advice?

I lurked and posted here for sometime getting my pond in shape (thanks!) and
am about to (sigh) enlarge my pond a bit in order to get the H2O circulating
better (guess I should have lurked a little more before starting).

I'll be using the liner prep, single sided and double sided tape, plus the
silicone caulk that seems to be the way to go. My only hesitation is that I
don't plan to pull the liner all the way out, thus it won't be flat when I
do the seaming.

Any final advice?