Adam, what have you been doing all these years as a golf writer if you haven't been to Brora! It is wonderful because it asks all sorts of questions of your game: can you shape long shots to hold a green? Can you cope with different stances? Par 4s of varying lengths (the first three are 297 (to a wicked green), 344 and 447 mean you have to think hard about club selection and how you flight the ball. The greens are shaped to test the conviction of your putting stroke.
It has par 3s of 190, 162, 125 and 201 (the final hole that is more like a par 4 because it is so uphill) and all at different angles to the wind with wildly different greens. You are right about 6, not least because of the funny little grassy mound on the right of the green, which forces you to chip across that terrifying right to left slope.
There are lines of enchantment from the tee that can lead to proper bother — I think it is 10 that is next to the railway line, which gives everyone pause for thought, like 4 at Woking. Go left and it all becomes much harder with bunkers, rough and a tough angle to the green.
All the while the course provides ground conditions that generally allow you to get at the ball if you end up off line. I really love the course conditioning, so much so that I wish all links courses were kept by livestock.
I really enjoy RD too. It is genuinely spectacular to look at and really questions your choice of club off the tee -- driver is not always the sensible option but there are wonderful little speed slopes that, if you can hit them, take your ball way down the fairway and give you a short iron in. My overall impression is that you have to be brave at Dornoch, it punishes timidity as you would expect of a top class test. It is mentally tiring because you have to concentrate so hard but, having only been twice, I suspect playing it regularly would take some of the fear factor away.
If I were lucky enough to have them close by? RD is all about the first shot and keeping it out of the gorse, so once a month would be great. Brora encourages recovery and experimentation, so every week would be just fine (along with a blast of fun regularly at Fortrose & Rosemarkie!)