Jim, as usual you are “spot on”, mind like a steel trap—Ian Allan mag, and also your sizes are good too.
Took a look at what I had, and there is a Bantam 19 in 41in version, but it’s suggested a 23 would be okay too—-really? I don’t think it would be so good personaly.
Re. the spars—-agree, awfull way to build a wing, but I have done a couple of Interceptors that do it that way. Still have a nice one with a Burford 2cc Deezil in it, that flys quite well, but the one I did in the 70s with an O&R 23 on spark was so heavy that it glided like a brick, then when it arrived
am sure you guys can guess. Repair, repair, repair.