Ennis, I spoke to my conservationist house mate and she said it is best not to have the box with your book on your wall if the book is upright in the box as gravity will put pressure on the spine and eventually damage it. She said the book should be kept flat in the box. As for the pages- what the fellow told you is right- any preserving done on the pages will in time cause further damage and it is better to keep it in the conservation box where it will be in a special enviornment (not too humid, not too dry) and when turning the pages to wear vinyl or rubber gloves (not cotton as the fibres will rub on the paper).She said paper conservation might improve with technology.
I showed her my Mrs Beeton's 1897 recipe book which I have sellotaped the loose pages- I thought she would throw up her hands in horror!- but she said sellotape is ok only it yellows. I have glued the spine covering on it with PVA glue which was already off it when I got it. The book is in poor condition so it would never be worth anything now (I got it for 10p)- but if it was minor page tears and it was worth lots I would have had it done properly. I'm keeping it for historical interest and some of the pickle recipes (great for me- sugar free!!!). I'm keeping it lying flat as it is fragile.