Hi Howard, as to the size of harps suitable for performance in public places, I can’t say much. Partly it has to do with the model of the harp and partly with suitable amplication.
The L&H Prelude is very popular with people who love a classical harp sound and who may like to play a pedal harp later and/or because it offers a lot of harp for a relatively nice price. I have no intention to buy a pedal harp, mainly because I can play everything I want to play on my Prelude.
You said you saw a second hand Prelude being offered. Some older Preludes have 38 strings instead of 40 strings and these old harps miss the low A and the low B. No big problem, but I would really miss these two lowest strings.
As far as comparing a L&H Prelude to a Salvi Ana. In Europe (where I live, but perhaps not in the US) the Salvi Ana’s are not strung with pedal gut, but with folk gut. I prefer the sound of pedal gut, but this is personal. There are lots of people who prefer the sound of a Salvi Ana.
There are three main reasons why I bought a Prelude:
1. I prefer the sound of the strings of the higher register of the Prelude, as these strings sounds warmer and richer in my ears (even with the nylon strings that nowaday are on the higher strings and which can be changed into pedal gut strings after a year or so when the harp has completely stabilized)
2. The Performance levers of the Prelude work nicer than the Chinese ‘plug-and-play’levers of the Salvi’s. I have heard though that these have recently improved, so maybe, this isn’t relevant any longer.
3. The L&H Prelude is a lot cheaper than the Salvi Ana (at least in Europe).
As to cross strings and double strings: these are nice when you like to invent your own arrangements. There are a few books that I know of. When you like to play classical lever harp repertoire, I would buy a… lever harp. 🙂
Celtic ornamentation is seldom written out. There are several embellishments which one can choose to eh.. embellish celtic songs. There’s a book from the eighties: Allison Kinnaird ‘The Small Harp: a Step by Step Tutor’ which explains several of the embellishments in Scots music. It comes with a cassette… There must be newer methods, but I don’t know them.
Anyway, to play celtic music, you’d better not choose a harp with pedal gut tension, or it would be rather hard to play the very heavy strings very quickly and still sound nice. If you love celtic music, perhaps one of the Dusty nylon strung harps would be a better fit.
If you don’t have a car, I think it’s relevant to consider how you plan to transport your harp to the places you like to perform.
As to the way the harp is tilted: it should be supported by the floor and just rest very lightly to your shoulder. You could also use your knees to stabilize the harp. The strings should be (almost) perfectly vertically while you play.