Choice of recipient. Choose a breed that will naturally cycle at the time of year you are flushing.
For example, Charollais x may be better than mules in July.
Some early season breeding sheep:
Most recipients would be crosses, this maintains hybrid vigour. A suffolk x Mule would be a useful fairly early season recip for say August time.
Pure breeds such as the Texel as recipients may not be ideal as often lamb size/pelvis size becomes an issue.
Like wise Milk Sheep tend to work better as crosses.
Later season breeding sheep:
Mules (Scotch, North of England or Welsh)
Some people buy their recipients a year in advance so they have time to MV accredit them, or just so they can acclimatise to the farm. Thus buying hoggs or gimmer lambs in the season prior to carrying out the work may be sensible. If you have texels, tupping the bottom end with a charollais to produce some early season recipients may be useful. Any males born still make decent commercial cross tups.