Please bear in mind there are frequently over 100 users accessing this forum, which is a heck of a lot more than many others I read, with most accessing searching and dowloading content.
In my experience, 100 users is a very small number indeed ! On one forum for another interest I pursue , there are normally between 5,000 to 10,000 users on the site and it has peaked at over 12,000. For a small UK site dealing in a particular niche aspect of the same interest, there is normally five hundred on line at any one time, peaking at just under a thousand, without any problems.
There is obviously something amiss at the server end and I feel really sorry for Martin and those others helping, trying to sort all this out, as it must be highly frustrating and also very time consuming for all involved.
I know that I, like everyone else, am very grateful for the time effort and dedication put into it all as I really missed the site when it was down for a while but as we all know these 504 errors are a daily occurrence now, I'm sure Martin's blood pressure in particular will improve no end when it's sorted and he'll love being able to get out in the fresh air occasionally again.