Hi . Personally I’d be happy with 22 or similar and can imagine the difficulties with calculating the rotation of units that aren’t equally sized in X and Y. From memory I think XCom Apocalypse had multi-tile units, but I can’t recall whether they were all 22s. The earlier versions of XCom also stored the direction of the unit and there was an AP cost for changing which way you faced (not something I necessarily miss!), so that might be helpful to look at?
Have you found a way for this to work with hex grids, or is this limited to square grids only?
EDIT: Actually I’ve just checked and the Multiworm did indeed have a 2*1 tile coverage. I seem to remember some minor bugs / interesting features with how it moved though - at times it would appear that the worm took up 4 tiles when it was changing direction through a diagonal.