I agree with Kerstin that I wouldn't want to work so hard on the treadling! There are a couple of times when I have tied up my CM loom with a multi-treadle tie-up in order to achieve more complex options, namely for double cloth (where I assigned half the treadles to each layer, allowing me to mix blocks at will) and summer & winter (where I separated the tabby from the pattern blocks), but for twills and other basic weaves I'd much rather just get under the loom and organise the treadles for that particular project. But I always take a cup of tea down there with me, for sustenance!
Your problem sounds like a weaver's variant on "how long is a piece of string"! Really, it does depend on what you want to weave and how you plan to weave it. You have a big loom and may want to weave rugs or blankets on a scale to match, so you would then want pretty long warps. I have a fairly low boredom threshhold AND love warping my loom, so lots of shorter warps suit me well.
My Ashford warping board has a max warp length of about 11 yards, though I have only used that length once or twice. I believe there may be other boards going up to about 15 yards.