In reply to AMFMunro:
Unfortunately it's just impossible to say what weather and snow conditions will be like in mid-April - there's at least a possibility that you may find old hard snow and ice on the crests of Lui and Cruachan, so you might want to take advice much nearer the time. They're very fine hills but maybe neither is an ideal place to start winter hill-walking if you lack that experience.
Cruachan is a shapely rugged hill from any approach, and its ridges give fantastic views on a clear day, a top-quality Munro. One potentially awkward slabby step east of the main top has been the scene of accidents in the past, though it's easier when you're heading eastwards.
I agree with Wee Davie that the Cononish approach to Lui is very fine (despite the expanding gold mine). But again depending on your experience, Central Gully may be a bit demanding for you, especially on your own. The Glen Lochay approach to Beinn a'Chleibh and Lui is much less appealing, apart from the possible problems of getting across the river (which may need a wade, https://www.walkhighlands.co.uk/Forum/viewtopic.php?f=1&t=25867 ), over or under the railway (maybe another wade), and up through the forest (mucky and wet).
But in the right conditions either hill should give you a day to remember.