I would like to propagate a few dozen loquats, and cuttings would be more convenient than normal grafting. (It would give me 6 months to a year headstart over growing rootstock.)

Loquats cuttings do not root easily, though some success has been claimed using mist and rooting hormones.

I am going to try grafting a short piece of loquat (or pear) root to the bottom of each cutting, to help get things started.

I assume (or hope) that rooting hormone will not harm an existing root piece, but would it interfere with the bonding (growing together) at the graft? The hormone would be to help the cutting to form its own roots. This would be especially important above pear which may eventually become incompatible. .