I had a really tough time finding the right tips for my ears with the encores. None of the supplied tips worked that well for me. When I first got them, I was actually pretty disappointed because even though I could get seals with some of the stock tips, there wasn't enough isolation so they sounded very thin and with only minimal bass. It seemed like none of the stock tips had enough mass/substance to provide me sufficient isolation.
What I actually ended up doing initially was turn the large pair of the supplied grey silicones inside out, take a small amount of sugru, rolled it into a thin cylinder, stuck it around the exposed shaft of the tip, flip the tip right side in, and then stick the tips with the sugru inside in my ears. I then kept them in there for about 90 minutes to let the sugru set and create semi-custom fit tips (after the initial 90 minutes I then carefully took the tips off the envores and left them alone to set for 24 hours). This actually worked pretty well, but I still wasn't totally satisfied.
I have also tried spiral dots, which had the same problem as all the stock silicone tips (sealed well but didn't isolate sufficiently). I tried spinfits, but they also didn't provide enough isolation (although I want to give these another go without pulling them as far down the shaft of the encores though as was suggested above).
Ultimately, however, what has been best for me are the large Rebound foam tips I got on amazon (https://www.amazon.com/gp/aw/d/B01H6IF1D4/ref=yo_ii_pd_dx_mr_1?ie=UTF8&pd_rd_i=B01H6IF1D4&pd_rd_r=KV4YVHBGM7NC6JTWEB7P&pd_rd_w=AiBtQ&pd_rd_wg=TEinm&psc=1&refRID=KV4YVHBGM7NC6JTWEB7P). ZNARI foam tips, which are also on amazon and are almost identical to the rebounds, also work really well. Complys were pretty good; however, I like the rebounds more because their foam is a little bit more like shire olives in that it is denser, squishier, and has a more durable coating on the outside, so they are lasting longer. The Rebounds and ZNARIs also quite a bit cheaper than comply, which is always nice