Help needed with pistons installation

I am converting a 1950's Allen analog organ console to MIDI, retaining the original pedals and keyboards which I have already rewired and midified.
My question relates to pistons. Can I use button contacts which are normally open, with spring loaded momentary press-to-contact action in conjunction with the Classic Organ Works parallel or matrix MIDI boards? Both of these boards have 61 contacts available. I have 24 or so contacts remaining on the pedal matrix MIDI board and 5 or 6 remaining on the parallel keyboards, which is probably sufficient for my needs. Indicator lights are a secondary issue. I think Classic has a board for that also.
The space behind the keyslips is not very deep and is just enough to take a short span button mount and wiring unless I do the kind of work that causes cabinet makers to wince.

Any pointers will be appreciated. Thanks. John

Hello John

Although I use a dismembered Yamaha keyboard to midify my pedals, the principle is the same - I use the remaining notes for my pistons. There is the issue that if you use the transposer you will "transpose" and therefore confuse your pistons, but as I never use it that's not a problem to me. In Hauptwerk you connect the organ pistons to the appropriate notes.

I also use momentary push button switches as the actual pistons. They're not quite as reliable or as easy to hit as real pistons, but they do work well.

Thanks for the fast response, Ian. Yes, of course, it's the 'false' notes that have to be matched to the Hauptwerk piston addresses. Thanks for confirming that it's OK to use momentary contact switches

I enjoyed reading your post on the "Cheaper manuals .." thread. It's very interesting how technology has developed to make the construction of these instruments very DIY friendly and relatively cheaply too for the enterprising builder. It's no wonder they have all but disappeared from retail stores.

I'll put up some photos eventually, but I'm not there yet. The Allen Co made a good job of the consoles in those days. There's plenty of working space within the rear cabinet and most importantly for me, anyway, the fascia panel under the music desk is deep enough to allow for two rows of tab stops. There's room for at least 96 if I was so inclined, but that is unlikely to happen for a two manual organ.

John