As often happens it depends somewhat on what you're doing elsewhere. I typically use a 32" column for the early '30's stuff, but I also like my arms extended a little more than some. I've also used a 36" and been comfortable, but in that case the extra length helped clear a mount issue, though it did put a bit more angle in the steering joint. The height of your seat cushion will impact the angle of the column, and that could change what you choose. Also, it depends on "the look" you like inside the cab. Personally I think a column looks better with the "bell" close to the bottom of the dash, with just a small amount of clearance (speaking stock style dash face here). Others seem to like having the wheel end of the column hangin' way out in space. To each his own.

My suggestion would be that you mock up the left side of the engine the way you want it, and the interior. Then use a broom handle or closet rod (hint, don't take one from the wife's side of the closet ) to mock up the column. Your steering wheel choice is important too. If you're using a dished wheel a shorter column is in order, a flat wheel can use a little more length. When you sit there and find the comfortable position for you (vroom vroom noises optional), that will help you determine the length using the rod. This will go much easier if you've got a helper. Keep in mind the joint angles when doing placement. And don't make the mistake of thinking you can be "sloppy" about placement believing that having a tilt mechanism will make up for it...........it won't. Especially if you're not mindful of foot clearance (which, as you've probably already figured out, is pretty tight on these narrow cowled cars). Get the column in the "best" position for you regardless of the tilt aspect, and then use the tilt to ease ingress and egress, or for change of position on a long road trip.

One last suggestion. Take a look at the column offerings from Flaming River. The ididit stuff is good quality, and lots of people use it because the company was one of the first on the scene, but to my eye their stuff is too "angular". Looks just a bit beyond home made. The Flaming River folks have invested in tooling to give the pieces a more "sculpted" look that some of us find more pleasing to the eye, in less in tension with the form of the overall interior.

Have fun.