Thanks for the feedback @bookmdanno. Let me know if you do decide to jump in. I think personally I wouldn't do it at this stage if I were you. Even though ASICs are low maintenance compared to GPUs, they are way more hard work than just buying coins. I have had to build a sound proof box. Will update about that in the next blog post. You could buy some second hand Batch 1 Z9 minis on ebay or your local equivalent (gumtree?). I've seen some around at reasonable prices which you could pick up and plug in same day. I haven't run the calculations on how hash rate affects difficulty but yes the relationship will be linear... double the aggregate hashing power, double the difficulty. This in fact is one of the only draw backs of entering the ASIC phase early, is that you get the fastest difficulty rises. Bitcoin is a very mature ASIC market so the curve is mainly being pushed up by the increasing supply of units rather than advances in efficiency.