I found a page with a download link for SMIRF here:

http://www.chessbox.de/Compu/schachsmirf.html

Do you have Smirfoglot to run it under WiBoard? For the latest WinBoard version, downloadable from WinBoard forum, I include Smirfoglot with the (optional) Chess-Variants profile of the install.

I never noticed a big advantage for white in any opening array, but my method of testing might hide it. White bias in normal Chess is 3-4%, so to measure changes of that you really have to measure at the 1% level, which means a 1000+ games. When I test for piece values I play that number of games, but usually I shuffle the array, and any particular aray is only played a few times. In addition, Fairy-Max is programmed to do its first 3 moves more or less randomly, to create even more diversity. So if there is a particular line that would give white a better advantage, it would not be played often enough to stick out of the statistical noise in the result.

I guess what would be needed is really avoid randomness as much as possible, and let the positio play by 1000 different engines. But I don't have that many engines. As an alternative I could try to program more randomness during the game, and less in the beginning. But the problem is that engines might prefer some opening line then, which need not be the best at all. Especially at fast time controls. In normal Chess most engines would have grave difficulty in rediscovering major opening lines known from theory, when they have to play without book. Some make an absolute mess of it even at long TC. Joker is actually pretty good at this, because it was designed to play (normal Chess) without book, and I tuned its evaluation to not make silly opening errors. But if this also works well in 10x8 is anybody's guess. I discovered a very bad misadjustment of Joker's way to score castling w.r.t. King Safety after castling, which in Schoolbook led it to destroy its own castling rights (because it could not find a way to castle within the horizon fast enough, like it always would in normal Chess).

I guess that the best way to test such things would be to create a small opening tree of likely moves by hand. Or perhaps run an engine in multi-PV mode to analyze early opening positions for a few minutes each, to get the best few moves in every position, and construct a tree from that. And then evaluate the leaves of that tree by using it as starting position for a deep analysis, or for a thousand fast games. And then propagate the scores or winning probabilities along the opening tree towards the root.

It is my personal opinion that immediate mate threats do not impact the white beas very much, anymore than the existence of fool's mate or shephard's mate have a big impact on openings of ordinary Chess. In fact threatening those latter mates are considered very poor opening moves. To my eye threatening mate with the Marshal looks much the same. It does not look like a good opening move, (which you would likely wanted to play when it did not make the mate threat), and the opponent will simply defend against the mate with a good development move, like advancing the attacked Pawn, or defending it with a Knight, or blocking the Marshall's path with a Knight

Even the arguments I have seen that the Capablaca is a bad because of its high white bias are strongly based on the assumption of piece values, considering many lines as 'losing' because they contain a (B+N) vs (R+N) trade. While in fact these trades might be favorable in reality, and just misevaluated because of underestimation of the (B+N) value. Part of what makes the Joker80-TJchess10x8 games so interesting is that these engines do have a very different opinion on the relative values of the superpieces, so that unequal trades occur quite often (e.g. A vs M or A vs. R+B). This gives several nice examples of an Archbishop slaughtering a Marshall or Queen.

P.S. after spending most of the day by being captivated by the Schoolbook match, I hosted the monthly on-line computer blitz tourney on my Internet Chess Server in the evening. And it really struck me how incredibly boring ordinary Chess was compared to the 10x8 games I had been watching in the afternoon...