Ah, yes I see what you mean, that would be beyond the top end of the MR range. I assume by your reply that accuracy is essential too when adding the rennet, not my usual guesstimation. I'm going to have to do some searching. Never mind, that's part of the fun of cheesemaking I suppose... I'm still glorying in the victory of finding the exact right pot for the job, and a splendid PVC water pipe on the side of the road which will make wonderful molds. (I just hope it's not a second-hand sewage pipe!)
Thanks again Linuxboy, for all your advice.
Edit: I apologise Linuxboy, I have just done some more reading on this site and find that you have actually answered this question many times, with additional information (fascinating). Your knowledge is impressive indeed, have you considered writing a book on the subject? (or have you already done so?) Just a collection of all your posts and replies on this site would make a comprehensive treatise on the subject. You and all the other experts here are most generous to share your knowledge so freely like this.