You should have no problem shooting Tmax 100 at ISO 50 using the Sunny 16 rule. Truth is that's what I would recommend to a person who wanted to try out Tmax 100 without doing proper metering/testing. Always better to slightly over-expose than under-expose. I've never used Ilfosol 3 so I can't comment on it, but there are many good developers out there that work just peachy with Tmax 100. Personally, I think a very good combo to use is Tmax100 and Rodinal(Adonal, R09 etc.). I use it with Tmax 100 and Tmy-2 400 as a stand developer( 1:100 for 60 min.) when I've shot in very harsh lighting like, say a heavy sunny snow scene. Or for normal scenes it's 1:50. I think every darkroom warrants a bottle of Rodinal and believe it's one of the best "standby developers" out there. You use so small of an amount that it makes the cost per roll almost nothing, it lasts forever on your shelf, it's extremely simple and easy to use and it gives great looking(sharp) negatives. So, if I were you and wanted to try a slightly different developer Rodinal would be it. Plus, it's been around in one form or another since before the first automobile hit the road and there is a ton on info on the NET about its use. Whatever you do have fun! JohnW