Appropriate tool for measuring longer warps What's the best method for measuring out a three meter plus warp? I do make felt from my tail trimmings but I prefer to keep wool wastage to a minimum 
On this occasion I'm doing a single colour warp with 160 pieces of wool. Tabby weaving on a ridged heddle.

For roughly 2m or shorter  I just use the back stick and a peg. Some of my concerns for using that method over a longer length is keeping the tension the same across each strand and I will have to take my loom to an art space to have enough space. I've used a mill once for an 8 shaft but i didn't like how little number you can put on. Would a board with custom length pegs be my best option?
Any time you dress your loom (put the warp threads on) via the indirect warping method (measure out your warp via a warping mill or board), you don't need to measure out all your warp threads together. If you are doing a project with 160 ends, you can use a warping mill or board to measure out two groups of 80 ends each, and put them on the loom one at a time. Here is a link to a YouTube video that shows a good way to store warp until you are ready to put it on your loom: https://www.youtube.com/watch?v=VQ1qNeSYBxs (You can also go to your favorite search engine and search for "how to warp chain" and find similar resources.)

A custom made warping board with extra long pegs sounds like it would be a great thing to have, but if you already have a mill or board, measuring out your warp in smaller groups is one way to make do.