Rootstock for grafting

[kevrow73]

I've thought about grafting in the past, but I've always been put off by the price of the F1 rootstock seeds, especially as since joining here the number of plants I grow has gone up from about five or six to about sixty.
It's too late in the season here, but this week for an experiment and as a bit of fun I've tried sowing a couple of alternatives, just to see if there is an improvement in growth rate.
The first is Marmande, which I read in an thesis a couple of years ago is usable.
Secondly a Bulgarian F1 called Stara Mechta which I've not grown before but reportedly has very good root growth and disease resistance.
The scion I've chosen is an F1 called Rosada which for the last couple of years I've tried but it's growth has been quite spindly, so thought it would be a good candidate to try.
I'll try to grow one or two without the rootstock to compare.
Just wondered if anyone had tried anything like this themselves and/or does anyone have any opinion as to my chances of success or abysmal failure .

Kevin