I'm a Trist player as well, I don't agree with with your main build with items. The build allows your Trist to be very perceptable to any hero with high AS/AD combination. I can see a Master Yi coming up and making his way with you. Your second item build is more similar to mine. Note, I play 3s and I'm not sure if it makes too much of a difference other than less time per segments in the game (early/mid/late game time). I follow the same skill tree. I begin with boots of speed, as most solo 3 matches, that bush is sacred some how. Once in a while I can get a kill waiting for them. I use exhaust and flash combo with the explosive shot. I get berserker boots, zeal, frozen mallet (hp boost/slow is a must), upgrade to phantom dancer, then infinity edge. My fifth item would be one to counter act a possible tank. If no tank, take a blood thirster or zekes hearld. My 6th would be a defensive item. No need to another PD because with rapid fire, you should have plenty of AS. I would get that Black Belt/stash (names slipping me) I can usually kill most targets in 4 hits. Tanks or other ad carries are normally my biggest problems but with this item build, AD carries fall quicker than me, tanks normally get exhausted and tossed around with rocket jump/ buster shot combo. Continue to shoot them down, and flash towards them while they escape to finish them, if needed. Remembering the Frozen mallet damage slows them.