I ordered a 12.5 dent heddle for my loom, which handles 12.5 threads per inch, which will weave a much finer cloth (and in case you're wondering, the heddles for this loom will all work for a trade-up loom, whenever I get one, even though the trade-up loom will be wider). The holes in this heddle are really small, meaning that I can only warp the loom with fingering weight yarn. Luckily, I have a lot (a LOT) of fingering weight yarn on hand.
Weaving plaid is tricky because not only do your selvedges have to be even, your stripes have to be even too. This job is complicated by the fact that I only have one shuttle (The Hub will make some for me this weekend, and I have a couple of plastic ones on the way, but right now? Just one), so I have to wind it with different yarn for every section. It's not hard, it just slows me down.