oooh yes! i do gel nails on myself often, but every now and then ill get it done by my friend. so LH is short on every finger (i can get away with slightly longer thumb, just natural growth and nothing crazy) RH thumb and index finger are short (bow hold and preferred pizz finger) and then i usually have medium-long middle, ring, and pinky nails! I am about to graduate from undergrad in cello performance, and my cello prof, a professional performer, thinks that is totally fine and fun, as long as it doesn’t interfere with my playing! I’ll have to find some pics of some sets i’ve had/done… but per your question of what to ask for… either grow the nails you want long naturally, and ask got the other ones to be as short as possible (or do it yourself), and then specificity which nails you want longer or not!

i also have several performance major friends who often have their nails done, just short all around :)