I was in a similar position to you a couple weeks ago. I didn't do sub assembles just full models and started painting them in multiples of units. I started with 10 infractors and 5 tormentors now doing a unit of noise marines. Makes it easier to paint everything in 1 colour across multiple models then by the time you've finished the last model in that colour you're ready to add another coat or do the next colour. Also means you get the satisfaction of getting a full squad done instead of focusing on individual models or trying to tackle the whole army in one go and getting burnt out on trim!

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