Good to see that there are so many gluttons for punishment here.
It is snowing again as I write this so I am desperately looking forward to a more springlike month... I am pretty sure I will go with my brand new Tamron 90/2.8 though I may have a bit of a learning curve I have been spoiled by the fact that most of the lenses I use regularly are small primes and this is more of a behemoth, size wise. I had debated my beloved 35 Macro Ltd which has been neglected of late but that may be better suited to June. I bought that lens and used it nonstop last June and I will be curious to see how much I have improved in that time (in large part due to the discipline of challenges like this).
Here's to a terrific May!