I've gotten bitten by the apple grafting bug, and after some initial successes have placed an order for around 20 scions or different varieties, and around 15 MM102 rootstocks (thickness unknown, the nursery doesn't list the details, and I've not heard back from them yet after making an inquiry), this was the most I could get my hands on of MM102, which is pretty much the most suitable for my region/yard size/pests and diseases resistance/etc, whilst still being available here in Australia (Bud. group rootstocks aren't very common here, and Geneva group rootstocks are commercial stock only).
My question is: due to having more scions than rootstocks, will there be any major issues with grafting 2 scions to a few of the rootstocks? i.e. slower in plant growth, weaker graft union sites, higher risk of graft failure, etc.
And a secondary question of: If it's perfectly ok to graft multiple in one step, what graft type and positioning should I use? (both at top with whip and tongue? one whip and tongue at top, and aside veneer lower down? two side veneer grafts? Skip the standard grafts and go straight to bug grafting?)
Looking around it seems that it's not common to see 1 step multi-scion grafting on fresh rootstock, so my info is scarce and my concerns are high.
Don't hesitate to ask me for more info!