Too much CPU even for personal relays? The one I play with stays at 99% idle. How much CPU does it take to sustain only 1000 filters (say, your followers connect directly to your phone relay)?
Full relay is too much CPU for phones. But p2p note copying from the followed people is a good idea.
Discussion
A "personal relay" with the phone owner as the only writer should be fine.
But p2p negentropy would be more efficient than a relay.