I actually would advise against using the Avios Availability tool - unless you enjoy frustration !

LHR <> LAX can be popular and I believe LAS is also a popular route.

Have you considered San Francisco and San Diego - BA fly to both of these destinations also.

I would suggest you have a look with AwardNexus - you can set this up to do automated searches for you and mail the results to you each day. You might find AwardNexus easier to use (you can search for J+F at the same time, for example) - it interrogates BA.com so the availability it shows is the same.

With regard to your question, the 241 is not useless at all; like most things, the less flexibility you show (and I don't mean this in a derogatory way) the less chance of success you stand.

BAH