Next time you're at Lowes or Home Depot buy one or two 5 gallon size, and three or four gallon size nylon mesh paint strainer bags.
I used to weigh out and pre-package my hops ahead of time into however many gallon strainer bags, and then I would just toss the proper bag into the boiling wort when needed.
I still weigh out the hops, but put them into plastic containers. I use the five gallon nylon bag and just dump the hops from the container into the one large bag and tea bag the whole thing. I'd also give it a little love from the stir paddle during the boil.
Only have to clean one bag, not a bunch of goo in the kettle, and I get the right hops into the boil at the right time with no stress.
I use a plastic spring clamp to clamp the five gallon bag to the side of the kettle. Don't let it touch the bottom.